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SJC-11961

     ISABEL KAIN & others1    vs. DEPARTMENT OF ENVIRONMENTAL
                             PROTECTION.



            Suffolk.    January 8, 2016. - May 17, 2016.

 Present:    Gants, C.J., Spina, Cordy, Botsford, Duffly, Lenk, &
                             Hines, JJ.


Department of Environmental Protection. Environment, Air
     pollution. Regulation. Administrative Law, Regulations.
     Declaratory Relief. Statute, Construction.



     Civil action commenced in the Superior Court Department on
August 12, 2014.

     The case was heard by Robert B. Gordon, J., on motions for
judgment on the pleadings.

     The Supreme Judicial Court granted an application for
direct appellate review.


     Jennifer K. Rushlow (Susan J. Kraham, of New York, &
Veronica S. Eady with her) for Conservation Law Foundation &
another.
     Jo Ann Shotwell Kaplan, Assistant Attorney General, for the
defendant.
     Phelps Turner & C. Dylan Sanders, for Isabel Kain & others,
were present but did not argue.

     1
       Shamus Miller, James Coakley, Olivia Gieger, Conservation
Law Foundation, and Mass Energy Consumers Alliance.
                                                                    2


     The following submitted briefs for amici curiae:
     Stephanie R. Parker for Clean Water Action & others.
     Edward J. DeWitt for Association to Preserve Cape Cod.
     Arthur P. Kreiger & Jessica A. Wall for William R. Moomaw &
others.
     Robert J. Muldoon, Jr., & Thomas Paul Gorman for David A.
Wirth.


     CORDY, J.   In this case, we are asked to decide whether the

Department of Environmental Protection (department) has

fulfilled its statutory mandate under G. L. c. 21N, § 3 (d)

(§ 3 [d]), which provides that the department "shall promulgate

regulations establishing a desired level of declining annual

aggregate emission limits for sources or categories of sources

that emit greenhouse gas emissions."   By the terms of the

enabling legislation, the Global Warming Solutions Act, St.

2008, c. 298 (act), these regulations were to be issued by

January 1, 2012, to take effect on January 1, 2013, and to

expire on December 31, 2020.   See St. 2008, c. 298, § 16.   The

department failed to take action by the statutory deadline, and

in November, 2012, a group of residents submitted a rulemaking

petition to the department seeking the issuance of regulations

pursuant to § 3 (d) to limit greenhouse gas emissions2 in the

Commonwealth.

     The department held a public hearing on June 13, 2013, to

consider the petition.   Shortly thereafter, it issued a written

     2
       Unless otherwise indicated, we use the terms "emissions"
to mean greenhouse gas emissions.
                                                                    3


statement addressing the petitioners' concerns and concluding

that it had complied with the requirements of the act, including

those set forth in § 3 (d).    The statement also referenced

specific regulatory schemes that the department had established

to reduce greenhouse gases, including prescribed limits on

sulfur hexafluoride leaks, a regional cap and trade market to

manage carbon dioxide emissions known as the Regional Greenhouse

Gas Initiative (RGGI), and a low emission vehicle (LEV) program

aimed at reducing automobile emissions.    The department further

stated that these initiatives, individually and in combination,

fulfilled the mandate of § 3 (d).   No further action was taken

by the department at that time.

    In August, 2014, the plaintiffs filed a complaint in the

Superior Court seeking declaratory relief, or in the

alternative, a writ of mandamus, on the grounds that the

department had failed to fulfil its statutory mandate under

§ 3 (d).   The parties agreed that their respective submissions

to the court could be treated as cross-motions for judgment on

the pleadings under Mass. R. Civ. P. 12 (c), 365 Mass. 754

(1974).    The department again took the position that the sulfur

hexafluoride, RGGI, and LEV regulations satisfy the mandate of

§ 3 (d).   Following a hearing in March, 2015, the judge

dismissed the plaintiffs' mandamus claim and entered judgment in

the department's favor based on his findings that the three
                                                                     4


regulatory initiatives cited by the department substantially

complied with the requirements of § 3 (d).   The plaintiffs

timely appealed, and we granted direct appellate review to

determine whether the department has met its obligations under

§ 3 (d).

     For the reasons discussed herein, we conclude that the

unambiguous language of § 3 (d) requires the department to

promulgate regulations that establish volumetric limits on

multiple greenhouse gas emissions sources, expressed in carbon

dioxide equivalents, and that such limits must decline on an

annual basis.   We further conclude that the sulfur hexafluoride,

RGGI, and LEV regulations fall short of complying with the

requirements of § 3 (d), because they fail to ensure the type of

mass-based reductions in greenhouse gases across the sources or

categories of sources regulated under each of the programs, as

intended by the Legislature.   Accordingly, we reverse the

judgment of the Superior Court.3

     Discussion.   This case was decided in the Superior Court on

the parties' cross motions for judgment on the pleadings.      See

Mass. R. Civ. P. 12 (c).   For the purposes of this appeal, we


     3
       We acknowledge the amicus briefs submitted by the
Association to Preserve Cape Cod; Clean Water Action,
Environmental League of Massachusetts, Massachusetts Climate
Action Network, Massachusetts Sierra Club, Mothers Out Front &
others; Alternatives for Community and the Environment, the town
of Duxbury, & Dr. William R. Moomaw; and David A. Wirth.
                                                                      5


assume to be true the allegations in the plaintiffs' complaint

and the exhibits attached thereto.     See Sliney v. Previte, 473

Mass. 283, 284 (2015).

     The plaintiffs sought a declaratory judgment, or in the

alternative, a writ of mandamus.     A party may seek a declaratory

judgment "in any case in which an actual controversy has

arisen."    G. L. c. 231A, § 1.   We interpret the "actual

controversy" requirement generously.    See Gay & Lesbian

Advocates & Defenders v. Attorney Gen., 436 Mass. 132, 134

(2002).    "[A] dispute over an official interpretation of a

statute constitutes a justiciable controversy for purposes of

declaratory relief."     Santana v. Registrars of Voters of

Worcester, 384 Mass. 487, 493 (1981), S.C., 390 Mass. 358

(1983).    Declaratory judgment is appropriate here because the

material facts are not disputed, and the plaintiffs challenge

only the department's interpretation of     G. L. c. 21N, § 3 (d).4

Moreover, we previously have recognized that "declaratory relief

may sometimes be necessary to ensure that an agency will fulfil



     4
       The plaintiffs also requested a writ of mandamus to compel
department to promulgate regulations that comply with G. L.
c. 21N, § 3 (d) (§ 3 [d]). Mandamus is an extraordinary remedy
reserved for circumstances where the court must "prevent a
failure of justice in instances where no other relief is
available." Service Employees Int'l Union, Local 509 v.
Department of Mental Health, 469 Mass. 323, 334, n.11 (2014).
Because declaratory relief is available in this case, mandamus
relief is not appropriate.
                                                                    6


its statutory mandate."   Smith v. Commissioner of Transitional

Assistance, 431 Mass. 638, 651 (2000).

     1.   Statutory framework.   We begin with an overview of § 6

of the act, which enacted the Climate Protection and Green

Economy Act, G. L. c. 21N (statute).     The act was developed

against the backdrop of an emerging consensus shared by a

majority of the scientific community that climate change is

attributable to increased emissions, as well as perceptions in

the Commonwealth that national and international efforts to

reduce those emissions are inadequate.    See Executive Office of

Energy & Environmental Affairs, Massachusetts Clean Energy and

Climate Plan for 2020 at 8 (Dec. 29, 2010); Executive Office of

Energy & Environmental Affairs, Determination of Greenhouse Gas

Emission Limit for 2020 at 1 (Dec. 28, 2010) (Secretary's

Determination).   See also Massachusetts v. Environmental

Protection Agency, 549 U.S. 497, 505 (2007) (petition by

Massachusetts, with other States, local governments, and private

organizations, arguing Environmental Protection Agency abdicated

responsibility under Clean Air Act to regulate emissions of four

greenhouse gases, including carbon dioxide).5    The act



     5
       See Environmental Protection Agency, Regulating Greenhouse
Gas Emissions under the Clean Air Act, 73 Fed. Reg. 44,355 (Jul.
30, 2008), in which the Administrator of the Environmental
Protection Agency (EPA) stated that the "Clean Air Act, an
outdated law originally enacted to control regional pollutants
                                                                    7


established a comprehensive framework to address the effects of

climate change in the Commonwealth by reducing emissions to

levels that scientific evidence had suggested were needed to

avoid the most damaging impacts of climate change.     Executive

Office of Energy & Environmental Affairs, Commonwealth of

Massachusetts Global Warming Solutions Act 5-Year Progress

Report at 17 (Dec. 30, 2013) (Progress Report).     In accordance

with these findings, the statute requires that, by 2050,

greenhouse gas emissions be reduced by at least eighty per cent

below 1990 levels.    G. L. c. 21N, § 3 (b).

    The same year that the act became law, the Legislature also

enacted companion legislation concerning "Green Communities,"

St. 2008, c. 169; "Oceans," St. 2008, c. 114; "Clean Energy

Biofuels," St. 2008, c. 206; and "Green Jobs," St. 2008, c. 307.

"Each act addresses a separate but related piece of the clean

energy economy."     See Report of the Senate Committee on Global

Warming and Climate Change, No Time to Waste, at 10 (Feb. 13,

2015).   The act and its companion statutes provide policymakers

with a broad array of tools, including "targeted and technology-

specific policies[,] . . . economy-wide and market-based

mechanisms," and renewable energy portfolio standards and energy

efficiency improvements, to advance a clean energy economy while



that cause direct health effects, is ill-suited for the task of
regulating global greenhouse gases."
                                                                      8


reducing emissions and addressing the unique threats that

climate change poses to the Commonwealth.     See Massachusetts

Clean Energy and Climate Plan for 2020, supra, Executive Summary

at 7.

     The act is one of the primary mechanisms for achieving

reductions in emissions, and is the sole piece of legislation

authorizing the establishment of legally binding limits on those

emissions in the Commonwealth.6    Secretary's Determination at 1.

The act represents a commitment by the Commonwealth "to the most

ambitious greenhouse gas reductions for a single state in the

entire country."     Progress Report at introductory letter from

the Secretary.     To ensure that the Commonwealth remains on track

to meet the reduction limit for 2050, the statute also includes

timelines for achieving specified benchmarks in greenhouse gas

reductions in 2020, 2030, and 2040.     G. L. c. 21N, § 3 (b).

     The act designates the Secretary of Energy and

Environmental Affairs (secretary) and the department as the



     6
       By enacting the Global Warming Solutions Act (act),
Massachusetts became one of three States in the United States to
establish legally binding limits on Statewide greenhouse gas
emissions. See Executive Office of Energy & Environmental
Affairs, Global Warming Solutions Act 5-Year Progress Report at
17 (Dec. 30, 2013) (Progress Report). In 2006, California's own
Global Warning Solutions Act was signed into law. See id. at 17
n.5. Massachusetts' act is based largely on California's
version of the law. Compare Cal. Health & Safety Code §§ 38500-
38599 (2014).
                                                                    9


entities primarily responsible for implementing the act.7     See

generally G. L. c. 21N.   The design of the act is synergistic,

imposing numerous directives and timelines on the secretary and

the department to perform certain duties, subject to deadlines.

See St. 2008, c. 298, §§ 10-18.   These duties are to be

performed chronologically, and are largely contingent on one

another.   First, by January 1, 2009, the department was to

establish a greenhouse gas reporting regime and registry, which

permits the secretary to measure compliance with greenhouse gas

emissions reduction efforts.   See G. L. c. 21N, § 2 (a)-(c); St.

2008, c. 298, § 10.   Second, by July 1, 2009, the department was

to determine a baseline emissions level equal to the sum of all

emissions from Commonwealth sources for calendar year 1990 and

"reasonably project" what the emissions level would be in

calendar year 2020 "if no measures are imposed to lower

emissions other than those formally adopted and implemented as

of January 1, 2009" (known as business as usual level).      See

G. L. c. 21N, § 3 (a); St. 2008, c. 298, § 14.   Next, the

secretary was required, by January 1, 2011, in consultation with

the department and the Department of Energy Resources, to a

adopt Statewide emission limit for 2020 using the "business as

     7
       The Secretary of Energy and Environmental Affairs
(secretary) oversees the Commonwealth's six environmental,
natural resource, and energy regulatory agencies, including the
Department of Environmental Protection (department). See G. L.
c. 21A, §§ 1, 7.
                                                                     10


usual" baseline.8   See G. L. c. 21N, § 3 (b); St. 2008, c. 298,

§ 15.    Additionally, by the same date, the secretary was

required to adopt a limit for 2020 that was between ten and

twenty-five per cent below the 1990 emissions level, as well as

a plan for achieving said reduction.    See G. L. c. 21N, §§ 3 (b)

(1), 4 (a); St. 2008, c. 298, § 15.    Next, by January 1, 2012,

the department was to promulgate regulations pursuant to § 3 (d)

"establishing a desired level of declining annual aggregate

emission limits for sources or categories of sources that emit

greenhouse gas emissions."9   See St. 2008, c. 298, § 16.    These

regulations were to take effect on January 1, 2013.    Id.


     8
       As   noted, G. L. c. 21N (statute) also requires the
secretary   to adopt interim emissions levels for 2030, 2040, and
2050. G.    L. c. 21N, § 3 (b). The emissions level for 2050 must
be set at   least eighty per cent below the 1990 baseline. Id.
     9
       A "[g]reenhouse gas emissions source" is any "source, or
categories of sources, of greenhouse gas emissions with
emissions that are at a level of significance, as determined by
the secretary, that its participation in the program established
under this chapter will enable the secretary to effectively
reduce greenhouse gas emissions and monitor compliance with the
[S]tatewide greenhouse gas emissions limit." G. L. c. 21N, § 1.

     The department contends that the phrase "category of
sources" is not defined in the statute. To the contrary, the
phrase "sources or category of sources" is part of the
definition of "greenhouse gas emissions source" and plainly
refers to a source of greenhouse gas emissions.

     "Sources or category of sources" is a term of art in
environmental law, and refers to the process by which regulators
sometimes devise categories or subcategories of sources to
ensure that rules are implemented fairly and rationally as they
apply to a regulated source of greenhouse gas emissions. See,
                                                                      11


    It is undisputed by the parties that the department met

each of the statutory deadlines, except for the deadline for

promulgating the § 3 (d) regulations.      The department

promulgated initial emission reporting regulations in December,

2008, see 310 Code Mass. Regs. 7.71 (2013), and amended the

reporting requirements of the regulations in June, 2009, to

address reporting by sellers of retail electricity.         See

Progress Report at 18.    In July, 2009, the department published

a report establishing a 1990 baseline and projection of

Statewide greenhouse gas emissions for a likely "business-as-

usual" case to 2020.     Id.   In December, 2010, the secretary set

a Statewide limit on greenhouse gas emissions of twenty-five per

cent below the 1990 levels by 2020.      Id.   See Secretary's

Determination at 1.    At the same time, the secretary released

the comprehensive Massachusetts Clean Energy and Climate Plan

for 2020, discussed supra, in which he identified major sources

of greenhouse gases that should be addressed as part of the plan


e.g., 42 U.S.C. § 7412(e)(2) (1999) ("In determining priorities
for promulgating standards under subsection (d) of this section,
the Administrator shall consider . . . (C) the efficiency of
grouping categories or subcategories according to the pollutants
emitted, or the processes or technologies used"). The EPA has
often devised subcategories. See, e.g., 61 Fed. Reg. 27132 (May
30, 1996) (printing and publishing); 61 Fed. Reg. 46906 (Sept.
5, 1996) (polymers and resins); 61 Fed. Reg. 48208 (Sept. 12,
1996) (polymers and resins); 62 Fed. Reg. 49052 (Sept. 18, 1997)
(steel pickling); 63 Fed. Reg. 18504 (April 15, 1998) (pulp and
paper); 64 Fed. Reg. 27450 (May 20, 1999) (ferroalloys); 64 Fed.
Reg. 57572 (Oct. 26, 1999) (publicly owned treatment works); 67
Fed. Reg. 9156 (Feb. 27, 2002) (leather finishing).
                                                                   12


to reduce emissions.    See Progress Report at 18.   The

secretary's determination of the limit for 2020 was based on

analysis by the staff of the agencies under the secretary's

purview pursuant to the requirements of the statute, information

and reports gathered from the Climate Protection and Green

Economy Advisory Committee (established by the secretary),

public hearings, and written public comments.    Secretary's

Determination at 3-4.   His determination also took into account

that actions taken under other statutory mandates were expected

to produce Statewide greenhouse gas emissions reductions of

about eighteen per cent below 1990 levels.    Id.    See Eastern

Research Group Final Report to the Climate Protections & Green

Economy Advisory Committee, Initial Estimates of Emissions

Reductions from Existing Policies Related to Reducing Greenhouse

Gas Emissions, 2, 4, 6 (April 30, 2010) (Final Report),

available at

http://www.mass.gov/eea/docs/dep/air/climate/ergrptf.pdf

[https://perma.cc/8Q47-NGSA].    This eighteen per cent

calculation accounted for reductions associated with the LEV

program and the RGGI.   See Final Report at 2, 4, 6.

    Thus, to reach the twenty-five per cent reduction level by

2020, the Commonwealth would have to implement additional

measures to achieve approximately seven per cent in further

emissions reductions.   The parties agree that these reductions
                                                                   13


need not be attributable solely to regulations passed pursuant

to § 3 (d), but rather recognize that a variety of policies and

programs, including actions taken under other statutory

programs, such as the Green Communities Act, G. L. c. 7, § 9A,

may produce measurable reductions.     Secretary's Determination at

5.

     2.   Statutory language.    General Laws c. 21N, § 3 (d),

states that "[t]he department shall promulgate regulations

establishing a desired level of declining annual aggregate

emission limits for sources or categories of sources that emit

greenhouse gas emissions."      The plaintiffs interpret the

provision to require the promulgation of regulations that

address multiple sources or categories of sources of emissions,

impose a limit on emissions that may be released, limit the

aggregate emissions released, set emission limits for each year,

and set limits that decline on an annual basis.      They also claim

that the regulatory initiatives cited by the department fail to

comply with the requirements of § 3 (d).      The department

counters that § 3 (d) requires it only to establish aspirational

targets, or in the alternative, that it has substantially

complied with the mandate of § 3 (d) through its promulgation of
                                                                  14


the sulfur hexafluoride regulations and its amendments to the

RGGI and LEV regulatory schemes.10

     We review de novo questions concerning the meaning of an

agency's enabling statute.   See Commerce Ins. Co. v.

Commissioner of Ins., 447 Mass. 478, 481 (2006).   Where the

words in a statute are "clear and unambiguous," we them effect

as "the legislature's expressed intent."   Providence & Worcester

R.R. v. Energy Facilities Siting Board, 453 Mass. 135, 141

(2009).   If we conclude, however, that the statutory language is

"sufficiently ambiguous to support multiple, rational

interpretations," Biogen IDEC MA, Inc. v. Treasurer & Receiver

Gen., 454 Mass. 174, 186 (2009), then "we look to the cause of

its enactment, the mischief or imperfection to be remedied and

the main object to be accomplished, to the end that the purpose

of its framers may be effectuated" (citations and quotations

omitted).   Entergy Nuclear Generation Co. v. Department of

Envt'l Protection, 459 Mass. 319, 329 (2011).

     The department has "a wide range of discretion in

establishing the parameters of its authority pursuant to the


     10
       The department, in its brief, argues that § 3 (d) does
not require the creation of entirely new regulatory programs,
but rather that the department's amendments to existing programs
can satisfy the mandate of § 3 (d). We need not decide whether
an agency can comply with a statutory mandate to promulgate
regulations by referring to existing regulations, because we
conclude that none of the programs cited to by the department
complies with the requirements of § 3 (d).
                                                                  15


enabling legislation."   Moot v. Department of Envt'l Protection,

448 Mass. 340, 346 (2007), S.C., 456 Mass. 309 (2010), quoting

Levy v. Board of Registration & Discipline in Med., 378 Mass.

519, 525 (1979).   Nonetheless, statutory interpretation is

ultimately the duty of the courts, and for that reason, the

"principle of according weight to an agency's discretion . . .

is one of deference, not abdication, and this court will not

hesitate to overrule agency interpretations of statutes or rules

when those interpretations are arbitrary or unreasonable"

(citations and quotations omitted).   Moot, supra at 346.

    Moreover, our interpretation of statutes is not restricted

to determining only their "simple, literal or strict verbal

meaning" but also considers their "development, their

progression through the legislative body, the history of the

times, prior legislation, contemporary customs and conditions

and the system of positive law of which they are part . . . ."

Oxford v. Oxford Water Co., 391 Mass. 581, 588 (1984), quoting

Commonwealth v. Welosky, 276 Mass. 398, 401 (1931), cert.

denied, 284 U.S. 684 (1932).

    Taking these considerations together, we conclude that the

language of § 3 (d) is unambiguous, and, as detailed throughout

this opinion, we reject the department's interpretation of the

provision, which would tend to undermine the act's central

purpose of reducing emissions in the Commonwealth.
                                                                  16


    a.   Limits versus targets.   Because the question whether

§ 3 (d) requires the department to promulgate regulations

establishing binding limits on emissions or merely aspirational

targets is central to our determination of whether the agency

has met its obligations under the statute, we begin our

construction of the provision with the meaning of the word

"emission limits" as it appears in § 3 (d).   The plaintiffs

contend that the phrase "emission limits" requires the

department to issue regulations that establish binding caps on

sources or categories of sources of emissions; the department

argues that the phrase, as used in § 3 (d), requires it only to

promulgate regulations that establish aspirational goals or

unenforceable targets because the phrase is modified by the

phrase "desired level."

    With respect to this point, we are guided by two well-

established principles of statutory construction.   First, where

the same word is used in different parts of a statute, it

"should be given the same meaning . . . barring some plain

contrary indication."   CFM Buckley/North LLC v. Assessors of

Greenfield, 453 Mass. 404, 408 (2009), quoting Connolly v.

Division of Pub. Employee Retirement Admin., 415 Mass. 800, 802–

803 (1993).   Second, "[a]ll the words of a statute are to be

given their ordinary and usual meaning" and we construe "each

clause or phrase . . . with reference to every other clause or
                                                                  17


phrase without giving undue emphasis to any one group of words,

so that, if reasonably possible, all parts shall be construed as

consistent with each other so as to form a harmonious enactment

effectual to accomplish its manifest purpose."   Worcester v.

College Hill Props., LLC, 465 Mass. 134, 139 (2013), quoting

Selectmen of Topsfield v. State Racing Comm'n, 324 Mass. 309,

312–313 (1949).

     Applying these canons of interpretation, the parties agree

that the emissions reduction levels established by G. L. c. 21N,

§§ 3 (b) and 4 (a), are legally binding "[g]reenhouse gas

emission limits" as defined in § 1.11   See Secretary's

Determination at 1.   Despite this, the department asserts that

because § 3 (d) uses the term "emission limits" rather than the

statutorily defined term "greenhouse gas emissions limit," that

term is inapplicable to § 3 (d), and accordingly, regulations

promulgated thereunder need not set binding caps on emissions.

We disagree.   This argument ignores the fact that the term

"emissions limit(s)," unmodified by "greenhouse gas," appears

eight times in § 3 (b) and twice in § 4 (a).   In both of these

sections, however, there can be no doubt that the "emissions"

referenced are greenhouse gas emissions, and not emissions of


     11
       General Laws c. 21N, § 1, defines "[g]reenhouse gas
emissions limit" as "an authorization, during a specified year,
to emit up to a level of greenhouse gases specified by the
secretary, expressed in tons of carbon dioxide equivalents."
                                                                   18


some other type.   The same holds true for § 3 (d), which calls

for emission limits on "sources or categories of sources that

emit greenhouse gas emissions" (emphasis added).   It is apparent

from the plain language that § 3 (d) refers to "greenhouse gas

emissions limits" and that the term should accordingly be given

its statutorily defined meaning, which calls for a volumetric

cap on emissions, expressed in tons of carbon dioxide

equivalents.12

     The context in which the word "limits" appears also is

instructive to our determination of whether an actual cap on

emissions is required by § 3 (d).   The statute directs the

department to establish "desired level[s] of . . . emissions

limits" through the promulgation of regulations.   G. L. c. 21N,

§ 3 (d).   A regulation, by its definition, is not aspirational.

See Black's Law Dictionary, 1475 (10th ed. 2014) (defining


     12
       Because we concluded that the term "emission limits" as
it appears in § 3 (d) refers to the statutorily defined term
greenhouse gas emissions limits, we reject the department's
contention that the statutory requirement that limits be
expressed in carbon dioxide equivalents applies only to
"Statewide greenhouse gas emissions." G. L. c. 21N, § 1. This
argument ignores the definition of "greenhouse gas emissions
limit," which, by definition must also be expressed in carbon
dioxide equivalents. See note 11, supra. Moreover, the
department offers no reason why it cannot express limits in
carbon dioxide equivalents, which is how emissions reductions
are measured and reported in reports related to progress in
meeting the act's goals. See, e.g., Executive Office of Energy
& Environmental Affairs, Massachusetts Clean Energy and Climate
Plan for 2020, Executive Summary at 6 (Dec. 29, 2010); Progress
Report at 4, 12.
                                                                   19


"regulation" as "[c]ontrol over something by rule or restriction

. . .").   It is doubtful that the Legislature would require the

promulgation of regulations had it only meant for the department

to set aspirational targets, and if that was its intention, it

could have used the word "target" or "goal."13   Given this, we

see no indication that the Legislature intended to distinguish

between the term "emission limits" in § 3 (d) and its meaning as

defined in § 1 of the statute and as it is used in §§ 3 (b) and

4 (a).

     Second, giving the word "desired" its ordinary meaning, we

reject the department's position that the Legislature's use of

the word evinces its intent for the department to establish

target emissions levels rather than legally binding limits as

inconsistent with the manifest purpose of the statute.   Although

it is true that the word "desired" can mean "that is longed or

hoped for," the term is also defined as "predetermined to be

suitable or satisfactory; prescribed as requisite."   Webster's

Third New International Dictionary 612 (2002).   Taking this

definition together with the act's central aim of reducing

emissions in the Commonwealth, as well as the language of G. L.


     13
       The Legislature also could have used the statutorily
defined term "[e]missions reduction measures," which refers to
"programs, measures, standards, and alternative compliance
mechanisms authorized pursuant to this chapter, applicable to
sources or categories of sources that are designed to reduce
emissions of greenhouse gases." G. L. c. 21N, § 1.
                                                                   20


c. 21N, §§ 3 and 4, it is apparent that the Legislature ascribed

the latter meaning to the word "desired."   This interpretation

accounts for the fact that the Legislature, at the time it

enacted the statute, knew only that the emissions limit for 2020

would be set between ten and twenty-five per cent below the 1990

emissions level.   See G. L. c. 21N, §§ 3 (b), 4 (a).   Thus, by

using the word "desired" to modify "level," the Legislature

intended for the department to establish emission limits by

sources or categories of sources, and left it to the department

to determine what those limits would need to be to achieve the

compulsory reductions set by the secretary in accord with

§§ 3 (b) and 4 (a).

    The statutory deadline for promulgating regulations

pursuant to § 3 (d) lends further support to our interpretation

of the phrase "desired levels," especially in conjunction with

the statutory timeline, which required the department to

promulgate regulations after the creation of the greenhouse gas

emissions registry, the determination of the limit for 2020, and

the publication of the Secretary's plan for achieving the limit

for 2020, all of which would need to be considered in

determining both what sources of greenhouse gases to regulate,

as well as what emissions limits would be required with respect
                                                                     21


to those sources to achieve the reduction limit for 2020.14      A

"clearer statement is difficult to imagine" (citations omitted).

Attorney Gen. v. Commissioner of Ins., 450 Mass. 311, 319

(2008).   We thus conclude that the plain language of the statute

requires the department set actual limits for sources or

categories of sources that emit greenhouse gases through the

promulgation of regulations.

     b.   Remaining language.    We next examine the remaining

language of § 3 (d) and what it means for the department to

adopt "regulations establishing . . . declining annual aggregate

emission limits for sources or categories of sources that emit

greenhouse gas emissions."      G. L. c. 21, § 3 (d).

     The plaintiffs contend that the statute, by its terms,

requires the department to promulgate regulations that address

multiple sources or categories of sources of emissions, impose a

limit on emissions that may be released, limit the aggregate

emissions released from sources regulated by the department

pursuant to § 3 (d), set emissions limits for each year and

     14
       The department also argues that the sunset provision
associated with the § 3 (d) regulations supports its position
that the Legislature did not intend for actual limits on
emissions to be established under the provision. A more
sensible reading is that the sunset provision exists because
after 2020, new annual limitations on emissions would have to be
issued to ensure that Statewide limit for 2030, which has yet to
be established, will be met. In any event, the department's
interpretation of the sunset provision as meaning it cannot set
any limits under § 3 (d) would render the entire provision
meaningless, and is therefore not entitled to deference.
                                                                  22


establish limits that decline on an annual basis.    The

department disagrees, and argues that § 3 (d) only addresses

source-specific emissions and does not require the establishment

of Statewide emission limits by source category, which would

effectively limit the number of sources of greenhouse gases in

the Commonwealth, and not just emissions from those sources.

Although either approach might prove successful in reaching the

Commonwealth's over-all reduction goal, our obligation is to

determine which of these approaches the Legislature intended in

enacting § 3 (d).

    We begin by observing that the words "regulations,"

"emission limits," and "sources or categories of sources" appear

in their plural form in § 3 (d).   From this usage we may infer

that the Legislature intended for the department to regulate

multiple sources of greenhouse gas emissions.   See Leopoldstadt,

Inc. v. Commissioner of Div. of Health Care Fin. & Policy, 436

Mass. 80, 86-87 (2002) (court gives meaning to Legislature's

affirmative use of singular or plural form).    We therefore

reject the department's argument that each of the three

regulatory schemes individually satisfies the mandate of

§ 3 (d), as the plain language of the statute requires the

regulation of multiple groups of sources.   The central purpose

of the act is to effect significant reductions in emissions in

the Commonwealth, and that purpose would be frustrated if the
                                                                    23


department were to regulate emissions from only one group of

sources or categories of sources.    We therefore conclude that

the plain language of § 3 (d) requires the department to

regulate not all, but multiple, sources that emit greenhouse

gases.

    We next consider the meaning of the phrase "declining

annual aggregate emission limits for sources or categories of

sources."   The terms "emission limits" and "sources or

categories of sources" derive from the definitional section of

c. 21N.   Because the term "aggregate" is not defined in the

statute, however, we look to its ordinary meaning:     "formed by

the collection of units or particles into a body, mass, or

amount: collective."    Webster's Third New International

Dictionary 41 (2002).

    In this case, however, our interpretation hinges not on the

literal meaning of the word aggregate, but on the word or phrase

to which it applies.    Put differently, the question is whether

the plural usage of "aggregate emission limits" modifies sources

to be regulated, and requires that the emission limits imposed

on specified sources of emissions decline on an annual basis, or

whether, as the plaintiffs posit, it obliges the department to

establish annual Statewide caps on emissions in the years

leading up to 2020, which would result in the establishment of a

set of declining annual "aggregate emission limits."
                                                                    24


     Here, the plain language of the statute supports the former

interpretation, as there is nothing in the statutory language to

indicate that the department must regulate every source of

emissions in the Commonwealth.15    Indeed, plaintiffs acknowledge

that the department has discretion to select what sources of

emissions it will regulate pursuant to § 3 (d).16    Moreover, we

are cognizant of the fact that not all reductions in emissions

will be accomplished through the type of source-specific

regulation called for by § 3 (d).    Taking these considerations

together, it is evident that the phrase "aggregate emission

limits" modifies "sources or categories of sources," and thus

refers to the total mass of greenhouse gases emitted from each

regulated group of sources or categories of sources.    Finally,

it is apparent from the plain language of the statute that the




     15
       By its language, the statute accounts for the fact that
not all sources of greenhouse gases require regulation to
accomplish the Statewide reductions required by the statute.
See note 9, supra.
     16
        Although the department has discretion to choose which
sources to regulate under § 3 (d), the plaintiffs argue that,
even if the department's cited regulatory initiatives complied
with the provision's requirements, the department must regulate
a broader array of sources, and that it must do so through a
transparent decision-making process. Although we agree that
regulations contemplated under § 3 (d) are subject to the
requirements of the Administrative Procedure Act, G. L. c. 30A,
nothing in this opinion should be construed as requiring the
department to regulate a particular number of sources or type of
source.
                                                                   25


aggregate emission limits for each regulated source or category

of sources must decline on an annual basis.

    Thus, we conclude that the plain language of § 3 (d)

requires the department to promulgate regulations that address

multiple sources or categories of sources of emissions, impose a

limit on emissions that may be released, limit the aggregate

emissions released from each group of regulated sources or

categories of sources, set emissions limits for each year, and

set limits that decline on an annual basis.   Moreover, by the

design of the act, the department is well equipped to say what

actual reductions in emissions sources and source categories can

be achieved because it has already inventoried emissions from

every source and source category of emissions in the

Commonwealth pursuant to G. L. c. 21N, § 2.

    Our interpretation of § 3 (d) appreciates that, although

the department and the secretary have considerable expertise in

addressing the challenges that climate change poses to the

Commonwealth, it is ultimately for the Legislature to make

fundamental policy decisions.   The act makes plain that the

Commonwealth must reduce emissions and, in doing so, may, in

some instances, elevate environmental goals over other

considerations.   Thus, contrary to the department's assertions,

the Legislature's endorsement of a variety of emission reduction
                                                                 26


strategies17 does not preclude our finding that § 3 (d) requires

source-wide volumetric emissions limits.18   Moreover, such a

policy choice is entirely rational in pursuit of the statutory

goal of achieving legally mandated emissions reductions by

     17
       See, e.g., G. L. c. 21N, § 4 (b), which directs the
secretary to

     "analyze the feasibility of measures to comply with
     the emissions limit established in subsection (a).
     Such measures shall include, but not be limited to,
     the electric generating facility aggregate limit
     established pursuant to [§] 12, direct emissions
     reduction measures from other sectors of the economy,
     alternative compliance mechanisms, market-based
     compliance mechanisms and potential monetary and
     nonmonetary incentives for sources and categories of
     sources that the secretary finds are necessary or
     desirable to facilitate the achievement of reductions
     of greenhouse gas emissions limits."
     18
       Regulations issued pursuant to § 3 (d) may be
characterized as prescriptive regulations, or what are sometimes
called "command and control" regulations. See EPA, National
Center for Environmental Economics, Economic Incentives,
available at
https://yosemite.epa.gov/EE%5Cepa%5Ceed.nsf/webpages/EconomicInc
entives.html [https://perma.cc/NDD8-XMFW]. Prescriptive
regulations typically mandate how much pollution an individual
source is allowed to emit or what type of equipment must be used
to meet such requirements. EPA, Guidelines for Preparing
Economic Analysis, Regulatory and Non-Regulatory Approaches to
Pollution Control at 4-2 (Dec., 2010) (Pollution Control),
https://yosemite.epa.gov/ee/epa/eerm.nsf/vwAN/EE-0568-
04.pdf/$file/EE-0568-04.pdf [https://perma.cc/RX73-YN3W]. The
department points out that such regulations often use rates as a
means of prescribing emissions limitations, and that § 3 (d)
should be interpreted in this manner. However, "[b]ecause a
prescriptive standard is commonly defined in terms of an
emissions rate, it does not directly control the aggregate
emission level." Pollution Control, supra. Here, it is clear
that the Legislature intended, through its unambiguous language,
that the department issue prescriptive regulations that directly
control emission levels.
                                                                   27


2020.19   Where the Legislature has balanced public policy

concerns and chosen a course of action, it is not for the court

to second-guess its decision.    Wakefield Teachers Ass'n v.

School Comm. of Wakefield, 431 Mass. 792, 802 (2000).

     3.   Regulatory programs.   Having concluded what § 3 (d)

requires, we turn to the three regulatory initiatives cited by

the department as satisfying the mandate of § 3 (d).    We begin

by noting that the department does not dispute that it missed

the January 1, 2012, statutory deadline for promulgating

regulations pursuant to § 3 (d).   Moreover, based on our

interpretation of § 3 (d) as requiring declining annual

aggregate limits for regulated sources or categories sources of

emissions, it is apparent that the regulatory schemes on which

the department relies in this case do not comport with the

requirements of § 3 (d).


     19
       See, e.g., Balmes, California's Cap-and-Trade Program, in
Global Climate Change & Public Health, 383, 384 (Pinkerton &
Rom, eds. 2014) (noting that direct regulations account for much
larger proportion of emission reductions in California than
reductions attributable to State's cap-and-trade system);
Doremus & Hanemann, Of Babies and Bathwater: Why the Clean Air
Act's Cooperative Federalism Framework Is Useful for Addressing
Global Warming, 50 Ariz. L. Rev. 799, 799, 808 (2008) ("While
[carbon] trading has a place in the policy portfolio needed to
mitigate global warming, it alone will not be sufficient. . . .
Therefore, a regulatory strategy that just caps emissions from
electricity generating units -- such as the Regional Greenhouse
Gas Initiative [RGGI] emission trading system in the
northeastern states -- is unlikely to provide the scale of
[greenhouse gas] reduction required to address the problem of
global warming").
                                                                     28


     a.    Sulfur hexafluoride regulations.   Sulfur hexafluoride

is a "greenhouse gas" within the meaning of the act.20     G. L.

c. 21N, § 1.    The purpose of the sulfur hexafluoride regulations

is to achieve reductions in emissions.    310 Code Mass. Regs.

§ 7.72(1) (2014).    The regulations took effect in 2015, see 310

Code Mass. Regs. § 7.72(4), and proscribe excessive leakage of

sulfur hexafluoride from electrical power systems that are

insulated with this gas, known as gas-insulated switchgear

(GIS).    Id.

     The sulfur hexafluoride regulations create a scheme in

which maximum annual rates of allowable leakage for GIS in the

Commonwealth decrease on an annual basis.     310 Code Mass. Regs.

§ 7.72(1), (4).   The department has established a calendar of

decreasing rate limits, beginning with a 3.5 per cent leakage

rate allowed in 2015, and ending with a 1.0 per cent leakage

rate allowed in 2020.    310 Code Mass. Regs. § 7.72(5).   Any GIS

manufactured after 2015 must comply with the 2020 rate of 1.0.

310 Code Mass. Regs. § 7.72(4).   The rates are calculated by

dividing the total amount, in pounds, of sulfur hexafluoride gas

leaked by a facility over the previous year by the total sulfur

     20
       The EPA describes fluorinated gases like sulfur
hexafluoride as "the most potent and longest lasting type of
greenhouse gases emitted by human activities." See EPA,
Overview of Greenhouse Gases, Emissions of Fluorinated Gases at
1, available at
http://www3.epa.gov/climatechange/ghgemissions/gases/fgases.html
[https://perma.cc/NMN9-V9HT].
                                                                  29


hexafluoride gas capacity of all GIS in the facility.    310 Code

Mass. Regs. § 7.72(6)(b)(8).   Failure to comply with the

established rates is punishable by administrative penalties,

including the imposition of a fine not to exceed $25,000 per

violation.   See G. L. c. 21A, § 16; G. L. c. 111, § 142A.

    We agree with the plaintiffs that the imposition of

declining rates falls short of complying with the requirement of

§ 3 (d) that regulated sources are subject to a source-wide

volumetric cap on emissions.21 A rate, by nature of being a

ratio, is different from a limit, which sets a value that cannot

be exceeded.   Because the sulfur hexafluoride regulations impose

maximum rates as opposed to maximum limits on sulfur

hexafluoride emissions, an emitter permissibly could increase

its sulfur hexafluoride emissions by installing additional GIS.

Thus, the regulations control only the rate of leakage


    21
       In support of the sulfur hexafluoride and LEV
regulations, the department also contends that the statute, like
the Federal Clean Air Act, equates "emissions limits" with
"emissions limitations," permitting the expression of limits as
"rates." See 42 U.S.C. § 7602(k); G. L. c. 21N, § 1. We reject
this argument, as nothing in the language of the statute
indicates that the Legislature intended to incorporate terms or
definitions from the Clean Air Act.   Although G. L. c. 21N, § 7
(d), uses the term "emissions limitation," it does so in the
context of authorizing the Executive Office of Environmental
Affairs to "enforce any rule, regulation, order, emissions
limitation, emissions reduction measure or market-based
compliance mechanism adopted by the executive office or the
department pursuant to [the statute]." Contrary to the
department's assertions, this provision does not say anything
about how emissions limits may be expressed.
                                                                   30


permissible, and not the collective amount of sulfur

hexafluoride emissions that leak from GIS in the Commonwealth in

a given year.   Although these regulations will contribute to

reductions in sulfur hexafluoride emissions, they cannot ensure

the type of mass-based reductions contemplated by § 3 (d).

    The department argues that § 3 (d) does not require it to

cap emissions levels by groups of sources, because doing so

would effectively limit the number of sources of greenhouse

gases in the Commonwealth, as well as emissions from those

sources, rendering such regulations economically untenable, as

they would prevent new or expanding sources of greenhouse gases

from coming online.   To the contrary, the statute explicitly

contemplates that new or expanding sources of emissions will

come online in the Commonwealth.   See G. L. c. 21N, § 9

("Nothing in this chapter shall preclude, prohibit or restrict

the construction of a new facility or the expansion of an

existing facility subject to regulation under this chapter, if

all applicable requirements are met and the facility is in

compliance with regulations adopted pursuant to [the statute]").

To the extent that emissions limits may constrain new sources

from coming online in the future, such a consequence is one of

legislative making.   We note, however, that existing regulatory

schemes provide frameworks for how regulations can address

future emissions from new or expanding sources while ensuring
                                                                    31


that over-all emissions limits decline.22   Indeed, the

requirement of § 3 (d) that the aggregate mass of emissions from

a regulated group of sources be capped allows for flexibility to

create systems of allocation among sources within a category, in

contrast with a scheme that mandates stipulated reductions at a

discharge point, such as direct emissions reductions.     See G. L.

c. 21N, § 1.

     b. RGGI and carbon dioxide budget trading program.    In

accordance with G. L. c. 21A, § 22, department implemented a

carbon dioxide budget trading program, which tracks the model

rules of the RGGI and applies the RGGI standards in

Massachusetts.   See 310 Code Mass. Regs. § 7.70.   The RGGI is a

cap and trade program for electricity-generating facilities,

such as power plants, that emit carbon dioxide, which is a

greenhouse gas under the statute.   See G. L. c. 21A, § 22 (a);

     22
       See, e.g., the total maximum daily load program
established under the Clean Water Act, 33 U.S.C. § 1313(a)(1)
(2012); 40 C.F.R. § 130.2(i) (1989), which uses mechanisms such
as a "reserve capacity" to account for anticipated future
pollution. "Offsets" provide another means of accounting for
new or expanding sources of pollution, whereby future pollution
from new or expanding sources of pollution is offset through
mitigation measures. See, e.g., 9 Va. Admin. Code § 25-820-70
(2015) (requiring new or expanding facilities to offset
increased total discharges of nitrogen and phosphorus in
Chesapeake Bay). The design of the RGGI also permits new or
expanding sources of greenhouse gas emissions, as it applies to
all power plants in participating States that exceed a twenty-
five megawatt capacity, whether existing or future. See Regional
Greenhouse Gas Initiative, Inc., Fact Sheet,
http://www.rggi.org/docs/Documents/RGGI_Fact_Sheet.pdf
[https://perma.cc/S5Q6-DPZ7].
                                                                    32


G. L. c. 21N, § 1.    The RGGI established a market in which

carbon dioxide emitters in the participating States can buy and

sell a limited amount of emissions allowances.      See G. L.

c. 21A, § 22 (b).     The program establishes a cap on the amount

of carbon dioxide that power plants may emit by issuing a

limited number of tradable carbon dioxide allowances.     See

Regional Greenhouse Gas Initiative, Inc., Fact Sheet,

http://www.rggi.org/docs/Documents/RGGI_Fact_Sheet.pdf

[https://perma.cc/S5Q6-DPZ7] (Fact Sheet).     The number of

allowances issued for the emission of carbon dioxide is

determined by the maximum amount of carbon dioxide, measured in

tons (the cap), among the nine States participating in the

initiative.   Id.   The cap decreases by 2.5 per cent each year,

through 2020.   Id.

    Massachusetts joined the RGGI in 2007.      See Regional

Greenhouse Gas Initiative Inc., Program Design Archive,

http://rggi.org/design/history [https://perma.cc/MP4Z-62HX].

The Legislature subsequently required the department to adopt

rules and regulations in compliance with the RGGI to "limit and

reduce the total carbon dioxide emissions release by electric

generating stations."     G. L. c. 21A, § 22 (b).   Accordingly, the

department established the carbon dioxide budget trading

program, which incorporates the RGGI scheme into its regulations

and contains a schedule of the Commonwealth's annual "base
                                                                    33


budget," which declines by the requisite 2.5 per cent each year,

through 2020, when the base budget will be 12,617,227 tons of

carbon dioxide.   See 310 Code Mass. Regs. § 7.70(1)(a), (5)(a)

(2013); See Regional Greenhouse Gas Initiative Inc., The RGGI CO2

Cap, available at http://rggi.org/design/overview/cap

[https://perma.cc/T6V5-ATN6].

     We conclude that although the RGGI program and amendments

thereto are very important to the over-all regional scheme of

reducing carbon dioxide emissions, they do not qualify as a

regulation under § 3 (d).   The RGGI was established under G. L.

c. 21A, § 22, a statute entirely separate from the act.     There

can be little doubt that the Legislature, which directed the

department to adopt RGGI regulations in G. L. c. 21A, § 22, knew

of this preexisting statutory mandate when it enacted the act

and § 3 (d).   Indeed, reductions from the RGGI regulation were

accounted for in the eighteen per cent reduction in emissions

anticipated under the "business as usual" projection calculated

prior to the application of regulations under § 3 (d).    See

Final Report at 2.   Moreover, G. L. c. 21N, § 3 (c),

specifically carves out a separate process by which emissions

levels and limits associated with the electric sector are

established in consultation with the secretary and the

Department of Energy Resources and are to take into account the
                                                                  34


RGGI.23     By doing so, the Legislature recognized that a

significant part of the electric sector would already be subject

to regulations associated with the RGGI.     The RGGI is also

addressed extensively in G. L. c. 21A, § 22, lending further

support to the conclusion that the Legislature intended to treat

emission reductions associated with the electric sector

differently from other reductions in other sectors of the

economy.

       The department asks us to read the statutory provisions

together, as directing the department to promulgate regulations

establishing "a desired level of declining annual aggregate

emission limits," G. L. c. 21N, § 3 (d), and with respect to the

electric sector, "tak[e RGGI] into account," G. L. c. 21N, § 3

(c).    We disagree, as this reading ignores the Legislature's

intent that regulations related to electric sector be treated

differently from regulations promulgated under § 3 (d).

       Moreover, even if the Legislature intended for §§ 3 (c) and

3 (d) to be construed together, the RGGI still falls short of

complying with the requirements of § 3 (d) by virtue of the

auction feature, which permits a regulated carbon dioxide source

       23
       General Laws c. 21N, § 3 (c), requires that "[e]missions
levels and limits associated with the electric sector shall be
established by the executive office and the department, in
consultation with the department of energy resources, based on
consumption and purchases of electricity from the regional
electric grid, taking into account the regional greenhouse gas
initiative and the renewable portfolio standard."
                                                                     35


in one State to purchase allowances from any other State to meet

the compliance requirements.   See Fact Sheet, supra.    Under the

design of the program, if a Massachusetts power plant needed to

purchase allowances at the quarterly RGGI auction in order to

achieve compliance, and the allowances in the Massachusetts

carbon dioxide base budget were exhausted, the Massachusetts

power plant could purchase allowances from another participating

State.    Because of this feature, there is no way to ensure mass-

based reductions in carbon dioxide emissions from power plants

in the Commonwealth that participate in the RGGI.24     Thus, like

the sulfur hexafluoride regulations, the RGGI may contribute to

reductions in emissions, but does not comport with the specific

requirements of § 3 (d).    Any other interpretation would

diminish § 3 (d)'s purpose of achieving measurable and permanent

reductions to emissions in the Commonwealth.25


     24
       Relying on data sets apparently generated from the EPA
Air Markets Program Web site, the plaintiffs point out that
greenhouse gas emissions from regulated entities in Rhode Island
have increased under RGGI, exceeding the State budget and
requiring the purchase of additional carbon dioxide allowances.
EPA Air Markets Program data sets for carbon dioxide emissions
under RGGI in Rhode Island in 2010 and 2011 show an increase in
emissions by 87,609 short tons from 2009-2010 and 442,190 short
tons from 2010-2011.
     25
       Accordingly, we also reject the department's argument
that regulations promulgated pursuant to § 3 (d) need not
achieve greenhouse gas reductions specific to the Commonwealth,
but may be regional in nature. Not only is this argument
inconsistent with the statute's central purpose of reducing
emissions in the Commonwealth, but it also presumes the
                                                                   36


    c.     Low emission vehicle program.   The Federal Clean Air

Act establishes motor vehicle emission standards. Under the

statute, however, a State may obtain a waiver of Federal

preemption permitting it to adopt California's more stringent

emissions standards.    See 42 U.S.C. § § 7543, 7507.   In 1990,

Massachusetts adopted California's standards for regulating

motor vehicle greenhouse gas emissions.    See G. L. c. 111,

§ 142K, inserted by St. 1990, c. 510, § 2.     That statute also

required the department to establish and administer standards

for motor vehicle emissions based on California's standards.

G. L. c. 111, § 142K.   Pursuant to that statute, the department

promulgated regulations incorporating California's LEV

regulatory scheme.   See 310 Code Mass. Regs. § 7.40(1).     See

Cal. Code Regs., tit. 13, § 1961.3.    The LEV regulations set

exhaust and evaporative standards and regulate vehicle emissions

on the basis of the fleet-wide averages of individual automobile

manufacturers.   310 Code Mass. Regs. § 7.40.

    We conclude that the LEV regulations do not fully comply

with the mandate of § 3 (d).    The original promulgation of these

regulations significantly preceded the Legislature's adoption of

the act.   Although amendments to programs such as the LEV

program certainly advance environmental goals, they do not


department has authority to promulgate regulations that have
force outside the Commonwealth. Nothing in the language of the
statute or of G. L. c. 21A purport to do so.
                                                                  37


embody the change in "business as usual" required by the

Legislative mandate in the act.26    Indeed, the fact that the

Legislature was well aware of their existence and nonetheless

directed the department to promulgate regulations in accord with

new Statewide emissions limits is powerful evidence that neither

the LEV nor the RGGI program, nor amendments thereto, satisfies

the legislative intent of the act.    Although the LEV program has

been amended since the adoption of the act, the amendments were

made for the sole purpose of tracking exact changes to the

California regulations after which it is modeled, see Cal. Code

Regs., tit. 13, sec. 1961.3 (2014), which is required by the

Clean Air Act.   See 42 U.S.C. §§ 7543, 7507.   It is highly


     26
       The department also argues that, where the term
"regulations" is not defined in the act, the term should have
its normal meaning as reflected in the Administrative Procedure
Act, G. L. c. 30A, which defines the term "regulation" to mean
"the whole or any part of every rule, regulation, standard or
other requirement of general application and future effect,
including the amendment or repeal thereof, adopted by an agency
to implement or interpret the law enforced or administered by
it." G. L. c. 30A, § 1 (5). Although we agree that this
definition holds force, we reject the department's
interpretation that the definition requires a conclusion that
the LEV and RGGI programs and their amendments meet the
requirements of § 3 (d). Here, applying the literal
interpretation of the definition of "regulations" would require
us to ignore the over-all language and purpose of the statute,
as well as the Legislature's clearly expressed intent. We
decline to interpret the meaning of regulation so strictly in
this instance, where there is abundant support, in light of the
language and purpose of the statute, for the conclusion that the
Legislature intended for the department to regulate sources
additional to those already subject to well-established
regulatory schemes.
                                                                     38


unlikely that the Legislature passed the act so that the

department could promulgate regulations otherwise required by

Federal law.

     These considerations aside, the LEV amendments fall short

of the requirements of § 3 (d) because, like the sulfur

hexafluoride regulations, the LEV program regulates through the

imposition of rates, rather than actual caps on emissions.        The

LEV regulations do not ensure reduced emissions, but instead

established fixed rates of emissions from vehicles sold in

Massachusetts.     Thus, although the rate may remain constant or

even decline, the number of vehicles sold may increase.27    As a

consequence, the LEV regulations may contribute to lower

emissions from vehicles, but they cannot ensure that aggregate

emissions do not increase.     Therefore, they do not comply with

§ 3 (d).

     Conclusion.     Although the department's cited regulatory

initiatives are important to the Commonwealth's overall scheme

of reducing greenhouse gas emissions over time, they do not

fulfil the specific requirements of § 3 (d).     The purpose of

G. L. c. 21N is to attain actual, measurable, and permanent


     27
       The department seizes on this point to argue that the LEV
regulations could only satisfy § 3 (d) if there were a cap on
the number of motor vehicles sold in Massachusetts; however, the
plaintiffs do not propose such a rule, and instead argue only
that the LEV regulations do not meet the requirements of
§ 3 (d).
                                                                   39


emissions reductions in the Commonwealth, and the Legislature

included § 3 (d) in the statute to ensure that legally mandated

reductions are realized by the 2020 deadline.    Accordingly, we

vacate the judgment of the Superior Court and remand the matter

for entry of a judgment declaring that G. L. c. 21N, § 3 (d),

requires the department to promulgate regulations that address

multiple sources or categories of sources of greenhouse gas

emissions, impose a limit on emissions that may be released,

limit the aggregate emissions released from each group of

regulated sources or categories of sources, set emission limits

for each year, and set limits that decline on an annual basis.


                                   So ordered.
