A/HRC/37/59 Framework principle 11 States should establish and maintain substantive environmental standards that are non-discriminatory, non-retrogressive and otherwise respect, protect and fulfil human rights. Commentary 31. To protect against environmental harm and to take necessary measures for the full realization of human rights that depend on the environment, States must establish, maintain and enforce effective legal and institutional frameworks for the enjoyment of a safe, clean, healthy and sustainable environment. Such frameworks should include substantive environmental standards, including with respect to air quality, the global climate, freshwater quality, marine pollution, waste, toxic substances, protected areas, conservation and biological diversity. 32. Ideally, environmental standards would be set and implemented at levels that would prevent all environmental harm from human sources and ensure a safe, clean, healthy and sustainable environment. However, limited resources may prevent the immediate realization of the rights to health, food, water and other economic, social and cultural rights. The obligation of States to achieve progressively the full realization of these rights by all appropriate means 16 requires States to take deliberate, concrete and targeted measures towards that goal, but States have some discretion in deciding which means are appropriate in light of available resources.17 Similarly, human rights bodies applying civil and political rights, such as the rights to life and to private and family life, have held that States have some discretion to determine appropriate levels of environmental protection, taking into account the need to balance the goal of preventing all environmental harm with other social goals.18 33. This discretion is not unlimited. One constraint is that decisions as to the establishment and implementation of appropriate levels of environmental protection must always comply with obligations of non-discrimination (framework principle 3). Another constraint is the strong presumption against retrogressive measures in relation to the progressive realization of economic, social and cultural rights. 19 Other factors that should be taken into account in assessing whether environmental standards otherwise respect, promote and fulfil human rights include the following: (a) The standards should result from a procedure that itself complies with human rights obligations, including those relating to the rights of freedom of expression, freedom of association and peaceful assembly, information, participation and remedy (framework principles 4–10); (b) The standard should take into account and, to the extent possible, be consistent with all relevant international environmental, health and safety standards, such as those promulgated by the World Health Organization; (c) The standard should take into account the best available science. However, the lack of full scientific certainty should not be used to justify postponing effective and proportionate measures to prevent environmental harm, especially when there are threats of serious or irreversible damage. 20 States should take precautionary measures to protect against such harm; 16 17 18 19 20 14 See International Covenant on Economic, Social and Cultural Rights, art. 2 (1). See Committee on Economic, Social and Cultural Rights, general comment No. 3 (1990) on the nature of States parties’ obligations. See, for example, European Court of Human Rights, Hatton and others v. United Kingdom (application No. 36022/97), judgment of 8 July 2003, para. 98. See also Rio Declaration on Environment and Development, principle 11. See Committee on Economic, Social and Cultural Rights, general comment No. 3, para. 9. See Rio Declaration on Environment and Development, principle 15.