A/HRC/40/55 poor air quality and have systems in place to provide warnings when pollution poses an acute health threat, particularly for vulnerable populations. 68. In its general recommendation 32/2018, the National Human Rights Commission of Mexico described that country’s inadequate air quality monitoring system as a violation of the public’s right to environmental information and a violation of the right to a healthy environment. D. Establishing air quality legislation, regulations and standards 69. States have an obligation to “establish and maintain substantive environmental standards that are non-discriminatory, non-retrogressive and otherwise respect, protect and fulfil human rights” (A/37/59, annex, framework principle 11). WHO has published guidelines for ambient air quality as well as indoor air quality, which States should incorporate as legally binding national standards.32 In recognition of the different national contexts and capacities, WHO created interim guidelines for ambient particulate matter. The focus of the indoor air quality guidelines is on shifting to cleaner fuels and technologies for cooking, heating and lighting. These guidelines are under review because new evidence indicates that there is no safe level of exposure for some air pollutants, such as fine particles. 70. A global review of national air quality standards published in 2017 revealed that few States have incorporated the WHO guidelines into their air quality standards. 33 Not one State has adopted all of the WHO air quality guidelines, and only seven have adopted the most stringent WHO guideline for fine particulate matter. Incredibly, 80 States have no air quality standards or guidelines at all. Even in the European Union, air quality standards fail to meet the WHO guidelines. For example, the annual fine particulate limit is 2 1/2 times higher than the WHO recommendation. In the absence of strong standards, it is likely impossible to fulfil the right to breathe clean air. 71. Air quality standards should protect the most vulnerable members of society, in part by applying the precautionary principle and using adequate margins of safety. National standards must take into consideration the best interests of children.34 The complete absence or weakness of national air quality standards in many States indicates a widespread failure to fulfil this fundamental human rights obligation, with devastating impacts upon the health of children around the world. E. Air quality action plans 72. States must develop air quality action plans that identify the most important and effective measures that can be implemented to improve air quality, particularly for vulnerable populations. 73. Pursuant to principles of international human rights law, the right to breathe clean air is subject to progressive realization, recognizing that in some low- and middle-income States it cannot be immediately fulfilled. States have discretion to determine which air quality policies and programmes are best suited to their particular circumstances. However, they have obligations, to the maximum of their available resources (in some cases supplemented with international assistance), to implement concrete and effective measures to prevent increases in air pollution, improve air quality and fulfil the right to breathe clean air. Some obligations, such as non-discrimination and non-regression, are of immediate 32 33 34 12 WHO, WHO Guidelines for Indoor Air Quality: Household Fuel Combustion (Geneva, 2014); and WHO Regional Office for Europe, Air Quality Guidelines: Global Update 2005: Particulate Matter, Ozone, Nitrogen Dioxide and Sulfur Dioxide (Copenhagen, 2006). M.K. Joss and others, 2017. “Time to harmonize national ambient air quality standards for global health equity”, International Journal of Public Health, vol. 62, No. 4 (May 2017), pp. 453–462. Convention on the Rights of the Child, art. 3 (1).