OPINION OF THE COURT
Pigott, J.We hold that the New York City Board of Health, in adopting the “Sugary Drinks Portion Cap Rule,” exceeded the scope of its regulatory authority. By choosing among competing policy goals, without any legislative delegation or guidance, the Board engaged in law-making and thus infringed upon the legislative jurisdiction of the City Council of New York.
L
The New York City Board of Health is part of the City’s Department of Health and Mental Hygiene and consists of the Commissioner of that Department, the Chairperson of the Department’s Mental Hygiene Advisory Board, and nine other members, appointed by the Mayor. In June 2012, as part of its effort to combat obesity among City residents, the Department proposed that the Board amend article 81 of the City Health Code so as to restrict the size of cups and containers used by food service establishments for the provision of sugary beverages. After a preliminary vote by the Board, a notice of public hearing was published, seeking comments from the public. The substantial number of comments both before and during the July hearing indicated a groundswell of public interest and concern. On September 13, 2012, the Board voted, with one abstention, to adopt the Department’s proposed rule — referred to as the “Portion Cap Rule” — to go into effect in March 2013.
The Portion Cap Rule provides in relevant part that “[a] food service establishment may not sell, offer, or provide a sugary drink in a cup or container that is able to contain more than 16 fluid ounces” and “may not sell, offer or provide to any customer a self-service cup or container that is able to contain more than 16 fluid ounces” (NY City Health Code [24 RCNY] §81.53 [b], [c]). A “sugary drink” is defined as a nonalcoholic beverage that “is sweetened by the manufacturer or establishment with sugar or another caloric sweetener; . . . has greater than 25 calories per 8 fluid ounces of beverage; . . . [and] does *691not contain more than 50 percent of milk or milk substitute by volume as an ingredient” (NY City Health Code [24 RCNY] § 81.53 [a] [1]). The Portion Cap Rule does not apply to establishments, such as supermarkets and convenience stores, that are subject to regulation and inspection by the New York State Department of Agriculture and Markets.
II.
In October 2012, petitioners, six national or statewide not-for-profit and labor organizations, commenced this hybrid CPLR article 78 proceeding and declaratory judgment action seeking to invalidate the Portion Cap Rule. In addition to the Board of Health, the Department of Health and Mental Hygiene and its Commissioner are named as respondents.
On March 11, 2013, Supreme Court, New York County granted the petition, declared the Portion Cap Rule invalid, and permanently enjoined respondents from implementing or enforcing it. Supreme Court addressed two arguments raised by petitioners — first, whether the Board of Health had exceeded its regulatory authority “and impermissibly trespassed on legislative jurisdiction” (2013 NY Slip Op 30609[U], *11 [Sup Ct, NY County 2013]) and second, whether the Portion Cap Rule is “arbitrary and capricious” (id. at *35). The court ruled in favor of petitioners on both contentions.
With respect to the first issue, the court surveyed the history of the New York City Charter and reached the conclusion that the elective New York City Council is the sole legislative body in the City, rejecting respondents’ contention that the Board of Health has inherent law-making authority. Supreme Court applied our decision in Boreali v Axelrod (71 NY2d 1 [1987]), in which we held that the New York State Public Health Council overstepped its regulatory authority when it adopted regulations prohibiting smoking in a wide variety of indoor areas open to the public that had previously been considered, but not adopted, by the state legislature. Supreme Court addressed the four considerations that we had identified in Boreali, and concluded that each of those factors weighed in favor of invalidating the Portion Cap Rule (see 2013 NY Slip Op 30609[U] at *11-34). Finally, Supreme Court found the Portion Cap Rule arbitrary and capricious, noting that “it applies to some but not all food establishments in the City, [and] it excludes other beverages that have significantly higher concentrations of sugar sweeteners and/or calories” (2013 NY Slip Op 30609[U] at *35).
*692The Appellate Division unanimously affirmed Supreme Court’s order, also rejecting the contention that the Board has inherent legislative power, and holding that “under the principles set forth in Boreali, the Board of Health overstepped the boundaries of its lawfully delegated authority when it promulgated the Portion Cap Rule to curtail the consumption of soda drinks. It therefore violated the state principle of separation of powers” (110 AD3d 1, 16 [1st Dept 2013]). The Appellate Division did not reach the issue of whether the Portion Cap Rule is arbitrary and capricious.
With respect to the first Boreali factor, relating to whether the agency engaged in the balancing of competing concerns of public health and economic cost, thus acting on its own idea of sound public policy, the Appellate Division reasoned that the Board did not act solely with a view toward public health considerations but engaged in policymaking when it adopted the Portion Cap Rule. The court observed that the Portion Cap Rule is “especially suited for legislative determination as it involves ‘difficult social problems,’ which must be resolved by ‘making choices among competing ends’ ” (110 AD3d at 11, quoting Boreali, 71 NY2d at 13).
With regard to the second Boreali factor, whether the agency created its own comprehensive set of rules without benefit of legislative guidance, the Appellate Division concluded that the Board illicitly created the Portion Cap Rule on a “clean slate,” and was not merely conducting permissible interstitial rulemaking. The court noted that “the Board of Health does not dispute that neither the state legislature nor the City Council has ever promulgated a statute defining a policy with respect to excessive soda consumption” (id. at 13).
Turning to the third Boreali factor, which relates to whether the challenged rule governs an area in which the legislature has repeatedly tried to reach agreement in the face of substantial public debate and vigorous lobbying by interested factions, the Appellate Division noted that
“[o]ver the past few years, both the City and State legislatures have attempted, albeit unsuccessfully, to target sugar sweetened beverages. For instance, the City Council has rejected several resolutions targeting sugar sweetened beverages (warning labels, prohibiting food stamp use for purchase, and taxes on such beverages). Moreover, the State Assembly *693introduced, but has not passed, bills prohibiting the sale of sugary drinks on government property and prohibiting stores with 10 or more employees from displaying candy or sugary drinks at the check out counter or aisle. While the Portion Cap Rule employs different means of targeting the sale of certain beverages than those considered by the legislative bodies, it pursues the same end, and thus addresses the same policy areas as the proposals rejected by the State and City legislatures. This is a strong indication that the legislature remains unsure of how best to approach the issue of excessive sugary beverage consumption.” (Id. at 14-15 [footnotes and internal quotation marks omitted].)
Finally, with respect to the fourth Boreali factor, whether the development of the rule required expertise in the field of health, the Appellate Division concluded that the Board had not “exercised any special expertise or technical competence in developing the Portion Cap Rule” (110 AD3d at 15).
We granted respondents leave to appeal (22 NY3d 853 [2013]). Subsequently, we accepted amicus briefs from a number of not-for-profit organizations, research and policy centers, and professors of law, as well as 32 individual members of the New York City Council and the New York City Public Advocate. The quantity of these submissions is an indication of the interest of the subject to diverse persons, and the briefs have been of considerable assistance to us in our deliberations. We now affirm the Appellate Division’s order.
III.
First, we address respondents’ claim that the Board, having been created by the state legislature, has legislative powers separate and apart from the City Council. The City Charter unequivocally provides for distinct legislative and executive branches of New York City government. The City Council is the sole legislative branch of City government; it is “the legislative body of the city. . . . vested with the legislative power of the city” (NY City Charter § 21 [emphasis added]; accord Under 21, Catholic Home Bur. for Dependent Children v City of New York, 65 NY2d 344, 356 [1985]; Subcontractors Trade Assn. v Koch, 62 NY2d 422, 427 [1984]). The New York State Constitution mandates that, with an exception not applicable here, “[e]very local government . . . shall have a legislative body elective by *694the people thereof’ (NY Const, art IX, § 1 [a]; see also Municipal Home Rule Law § 2 [7]), and that elective body in New York City is the City Council.1
Respondents, however, contend that the Board of Health is a unique body that has inherent legislative authority. We disagree. The provision of the City Charter principally cited by respondents — setting out the authority of the Board to “add to and alter, amend or repeal any part of the health code, . . . [to] publish additional provisions for security of life and health in the city and [to] confer additional powers on the [Department of Health and Mental Hygiene] not inconsistent with the constitution, laws of this state or this charter” (NY City Charter § 558 [b]) — reflects only a regulatory mandate, not legislative authority. It is true that the Board “may embrace in the health code all matters and subjects to which the power and authority of the [Department of Health and Mental Hygiene] extends” (NY City Charter § 558 [c]) and that the Charter refers to the Board’s supervision over “the reporting and control of communicable and chronic diseases and conditions hazardous to life and health” and “the abatement of nuisances affecting or likely to affect the public health” (NY City Charter § 556 [c] [2]; see also § 556 [c] [9] [referring to Board’s authority to “supervise and regulate the food and drug supply of the city and other businesses and activities affecting public health in the city”]). Nonetheless, the Charter contains no suggestion that the Board of Health has the authority to create laws. While the Charter empowers the City Council “to adopt local laws . . . for the preservation of the public health, comfort, peace and prosperity of the city and its inhabitants” (NY City Charter § 28 [a]), the Charter restricts the Board’s rulemaking to the publication of a health code, an entirely different endeavor.
Moreover, the language in section 558 (c) of the Charter— describing the Board’s purview as comprising “all matters and subjects” within the authority of the Department of Health and *695Mental Hygiene — was included in 1979 to preclude the Board from attempting to regulate areas not related to health. At that time, the City’s Committee on Health became concerned that “[Regulations passed by the Board of Health may be overly broad and so invade the [province] of the City Council’s legislative authority” (Rep of Comm on Health in Favor of Approving and Adopting a Local Law to Amend the New York City Charter in relation to Defining Powers of Board of Health, Local Law Bill Jacket, Local Law No. 5 [1979] of City of NY). The Committee proposed a bill to clarify the Board’s authority, which was passed by the City Council in February 1979 and approved by the Mayor the following month (Local Law No. 5 [1979] of City of NY, amending NY City Charter § 558 [c]). Far from indicating a wide legislative jurisdiction, as respondents contend, section 558 (c) was intended to ensure that the Board of Health not regulate too broadly.
Respondents offer no practical solution to the difficulties that would arise from treating the Board and the City Council as coequal legislative bodies. On respondents’ theory, it is unclear what the law in New York City would be were the Board to pass a health “law” that directly conflicted with a local law of the City Council. It is no solution to this difficulty that the state legislature could step in to resolve such a conflict. In short, it is clear from the Charter that the Board’s authority, like that of any other administrative agency, is restricted to promulgating “rules necessary to carry out the powers and duties delegated to it by or pursuant to federal, state or local law” (NY City Charter § 1043 [a]). A rule has the force of law, but it is not a law; rather, it “implements or applies law or policy” (NY City Charter § 1041 [5] [i]).
Respondents point out our passing references to the Board’s “legislative authority” in Grossman v Baumgartner (17 NY2d 345, 351 [1966] [upholding Board’s former rule prohibiting tattooing by non-physicians]) and in a footnote in Matter of Schulman v New York City Health & Hosps. Corp. (38 NY2d 234, 237 n 1 [1975]). A more accurate description is found in the words we used to describe the Board’s rule earlier in the Grossman opinion: “an administrative regulation which is legislative in nature” (17 NY2d at 349).
Another of our cases cited by respondents, People v Blanchard (288 NY 145 [1942]), held that the Board may make it an offense to keep “unwholesome poultry” and a defendant may be convicted of a misdemeanor for violating that Sanitary Code *696regulation. But Blanchard stands for the proposition that, even though the Board does not possess “substantive law-making power” (id. at 147) and “has not been licensed to define any criminal offense” (id. at 148), it may pass a regulation with criminal consequences because “it is the city charter . . . and the Penal Law . . . that make any violation of the Sanitary Code a misdemeanor” (id.). Blanchard emphasizes the Board’s regulatory, as opposed to law-making, capacity.
IV
Given our position that the Board’s role is regulation, not legislation,2 the next issue raised in this appeal is whether the Board properly exercised its regulatory authority in adopting the Portion Cap Rule. The parties and the lower courts correctly analyze this question by using the conceptual framework of Boreali. Because a doctrine of “separation of powers [is] delineated in the City Charter” (Under 21, Catholic Home Bur. for Dependent Children, 65 NY2d at 353; see also id. at 356), Boreali provides the appropriate framework.
Boreali sets out four “coalescing circumstances” present in that case that convinced the Court “that the difficult-to-define line between administrative rule-making and legislative policy-making ha[d] been transgressed.” (Boreali, 71 NY2d at 11.) We explained that “[w]hile none of these circumstances, standing alone, is sufficient to warrant the conclusion that the [Public Health Council] has usurped the Legislature’s prerogative, all of these circumstances, when viewed in combination, paint a portrait of an agency that has improperly assumed for itself the open-ended discretion to choose ends” that is the “prerogative[ ] of [a] Legislature” (id. at 11, 18 [internal quotation marks and square brackets omitted]).
As the term “coalescing circumstances” suggests, we do not regard the four circumstances as discrete, necessary conditions that define improper policymaking by an agency, nor as criteria that should be rigidly applied in every case in which an agency is accused of crossing the line into legislative territory. Rather we treat the circumstances as overlapping, closely related factors that, taken together, support the conclusion that an agency *697has crossed that line. Consequently, respondents may not counter petitioners’ argument merely by showing that one Boreali factor does not obtain.
Any Boreali analysis should center on the theme that “it is the province of the people’s elected representatives, rather than appointed administrators, to resolve difficult social problems by making choices among competing ends” (71 NY2d at 13). The focus must be on whether the challenged regulation attempts to resolve difficult social problems in this manner. That task, policymaking, is reserved to the legislative branch.
V
In Boreali, the Court initially pointed out that the Public Health Council’s scheme for protecting nonsmokers indicated its “effort to weigh the goal of promoting health against its social cost and to reach a suitable compromise.” We took this to violate the principle that “ [striking the proper balance among health concerns, cost and privacy interests ... is a uniquely legislative function” (Boreali, 71 NY2d at 12). We reasoned that “to the extent that the agency has built a regulatory scheme on its own conclusions about the appropriate balance of trade-offs between health and cost to particular industries in the private sector, it was acting solely on its own ideas of sound public policy and was therefore operating outside of its proper sphere of authority” (id. [internal quotation marks and square brackets omitted]). Here, similarly, the Appellate Division noted that the Board of Health included exemptions and other indicators of political compromise in its Portion Cap Rule, notably the exclusion of food service establishments subject to the State Department of Agriculture and Markets. The Appellate Division interpreted this as evidence that the Board was engaged in policymaking, rather than simply in protecting the health of New York City residents.
However, the promulgation of regulations necessarily involves an analysis of societal costs and benefits. Indeed, cost-benefit analysis is the essence of reasonable regulation; if an agency adopted a particular rule without first considering whether its benefits justify its societal costs, it would be acting irrationally. We stated as much in Boreali, noting that “many regulatory decisions involve weighing economic and social concerns against the specific values that the regulatory agency is mandated to promote” (Boreali, 71 NY2d at 12). Therefore, Boreali should not be interpreted to prohibit an agency from attempting to *698balance costs and benefits.3 Rather, the Boreali court found that the Public Health Council had “not been given any legislative guidelines at all for determining how the competing concerns of public health and economic cost are to be weighed” (id.).
Here, instead of an outright ban on sugary beverages, the Board decided to reduce their consumption by the expedient of limiting maximum container size, thus making it less convenient for consumers to exceed recommended limits. The more cautious approach, however, does not save the Portion Cap Rule. By restricting portions, the Board necessarily chose between ends, including public health, the economic consequences associated with restricting profits by beverage companies and vendors, tax implications for small business owners, and personal autonomy with respect to the choices of New York City residents concerning what they consume. Most obviously, the Portion Cap Rule embodied a compromise that attempted to promote a healthy diet without significantly affecting the beverage industry. This necessarily implied a relative valuing of health considerations and economic ends, just as a complete prohibition of sugary beverages would have. Moreover, it involved more than simply balancing costs and benefits according to preexisting guidelines; the value judgments entailed difficult and complex choices between broad policy goals — choices reserved to the legislative branch.
Significantly, the Portion Cap Rule also evidenced a policy choice relating to the question of the extent to which government may legitimately influence citizens’ decision-making. In deciding to use an indirect method — making it inconvenient, but not impossible, to purchase more than 16 fluid ounces of a sugary beverage while dining at a food service establishment— the Board of Health rejected alternative approaches, ranging from instruction (i.e. health warnings on large containers or near vending machines) to outright prohibition. This preference for an indirect means of achieving compliance with goals of healthier intake of sugary beverages was itself a policy choice, relating to the degree of autonomy a government permits its citizens to exercise and the ways in which it might seek to modify their behavior indirectly.
*699By choosing between public policy ends in these ways, the Board of Health engaged in law-making beyond its regulatory authority, under the first Boreali factor. Notably, such policy-making would likely not be implicated in situations where the Board regulates by means of posted warnings (e.g. calorie content on menus) or by means of an outright ban of a toxic substance (e.g. lead paint). In such cases, it could be argued that personal autonomy issues related to the regulation are nonexistent and the economic costs either minimal or clearly outweighed by the benefits to society, so that no policymaking in the Boreali sense is involved.
To apply the distinction between policymaking and rulemaking, a court is thus required to differentiate between levels of difficulty and complexity in the agency’s task of weighing competing values. For example, when an agency regulates the purity of drinking water, or prohibits the use of interior lead paint, or requires guards in the windows of high-rise apartments housing children, it chooses among ends (e.g. a landowner’s convenience and short-term profit versus the safety, health and well-being of tenants), but the choices are not very difficult or complex. This is because the connection of the regulation with the preservation of health and safety is very direct, there is minimal interference with the personal autonomy of those whose health is being protected, and value judgments concerning the underlying ends are widely shared.
By contrast, when an agency in our present time either prohibits the consumption of sugary beverages altogether or discourages it by regulating the size of the containers in which the drinks are served, its choices raise difficult, intricate and controversial issues of social policy. Few people would wish to risk the physical safety of their children who play near high-rise apartment windows for the sake of unobstructed views. However, the number of people who overindulge in sugary drinks, at a risk to their health, is clearly significant. An agency that adopts a regulation, such as the Portion Cap Rule or an outright prohibition of sugary beverages, that interferes with commonplace daily activities preferred by large numbers of people must necessarily wrestle with complex value judgments concerning personal autonomy and economics. That is policy-making, not rulemaking.
VI
With respect to the second Boreali factor, respondents are unable to point to any legislation concerning the consumption of *700sugary beverages by the state legislature or City Council that the Portion Cap Rule was designed to supplement. Although “[t]he Legislature is not required in its enactments to supply agencies with rigid marching orders” and the legislative branch may, while declaring “its policy in general terms by statute, endow administrative agencies with the power and flexibility to fill in details and interstices and to make subsidiary policy choices consistent with the enabling legislation” (Matter of Citizens For An Orderly Energy Policy v Cuomo, 78 NY2d 398, 410 [1991]), the policy choices made here were far from “subsidiary.” Devising an entirely new rule that significantly changes the manner in which sugary beverages are provided to customers at eating establishments is not an auxiliary selection of means to an end; it reflects a new policy choice. In short, this is not a case in which “the basic policy decisions underlying the [challenged] regulations have been made and articulated by the Legislature” (Bourquin v Cuomo, 85 NY2d 781, 785 [1995], quoting Matter of New York State Health Facilities Assn. v Axelrod, 77 NY2d 340, 348 [1991]).
Therefore, it is clear that the Board of Health wrote the Portion Cap Rule without benefit of legislative guidance, and did not simply fill in details guided by independent legislation. Because there was no legislative articulation of health policy goals associated with consumption of sugary beverages upon which to ground the Portion Cap Rule, the application of the second Boreali factor generates the same conclusion as the first factor: the adoption of the rule involved the choosing of ends, or policymaking.
VII.
With regard to the third Boreali factor, little needs to be added to the Appellate Division’s analysis. We again caution, however, that the Boreali factors do not constitute rigid conditions, all of which must be met in order for petitioners to prevail. Here, inaction on the part of the state legislature and City Council, in the face of plentiful opportunity to act if so desired, simply constitutes additional evidence that the Board’s adoption of the Portion Cap Rule amounted to making new policy, rather than carrying out preexisting legislative policy.
In light of Boreali’s central theme that an administrative agency exceeds its authority when it makes difficult choices between public policy ends, rather than finds means to an end chosen by the legislature, we need not, in this appeal, address *701the fourth Boreali factor: whether special expertise or technical competence was involved in the development of the rule. We do not mean to imply that the fourth factor will always lack significance. A court might be alerted to the broad, policy-making intent of a regulation, and the absence of any perceived need for agency expertise, by the fact that the rule was adopted with very little technical discussion. Here, regardless of who or which arm of government first proposed or drafted the Portion Cap Rule, and regardless of whether the Board exercised its considerable professional expertise or merely rubber-stamped a rule drafted outside the agency, the Portion Cap Rule is invalid under Boreali.
VIII.
In sum, the New York City Board of Health exceeded the scope of its regulatory authority by adopting the Portion Cap Rule. Supreme Court properly declared the rule invalid and enjoined its implementation.
Accordingly, the order of the Appellate Division should be affirmed, with costs.
. We are aware that historically the City Council once shared legislative functions with the body known as the Board of Estimate, notwithstanding the language of the Charter (see generally Board of Estimate of City of New York v Morris, 489 US 688 [1989] [declaring the voting system of the Board of Estimate unconstitutional]). In November 1989, however, the voters of New York City approved changes to the Charter that eliminated the Board of Estimate, thus making the City Council “the sole legislative body of the City” (Frederick A. O. Schwarz, Jr. & Eric Lane, The Policy and Politics of Charter Making: The Story of New York City’s 1989 Charter, 42 NYL Sch L Rev 723, 828 [1998]).
. It appears that the dissenting Judges do not disagree. Notably, the dissent, at the conclusion of a survey of legislative history and case law touching on the Board’s powers, concludes not that the Board’s authority is legislative, but that it is “at least ‘nearly legislative’ ” (dissenting op at 709; see also id. at 710 [referring to the Board’s “authority to regulate” and its “regulations”]).
. Even assuming, for the sake of argument, that the Board’s exemption of food service establishments subject to the Department of Agriculture and Markets was a matter of choice rather than necessity, the limited scope of the Portion Cap Rule would not in itself demonstrate that it amounted to policy-making.