A/HRC/37/54 have become part of customary international law and which reflect the general principles of law. 28. While many human rights norms are subject to qualifications and limitations, fiscal consolidation and economic reform measures should never violate the minimum core content of economic, social and cultural rights, nor be directly or indirectly discriminatory or result in the adoption of impermissible retrogressive measures in terms of the enjoyment or implementation of economic, social and cultural rights. The prohibition of impermissible retrogression in human rights law is the key economic, social and cultural rights standard for assessing rights-harming fiscal consolidation and economic reform measures. Retrogressive measures — that is, taking steps that would reduce the enjoyment of economic, social and cultural rights — are only permissible under certain strict circumstances (see below). 29. The onus is on governments to demonstrate that their proposed response measures will meet their human rights obligations. States, and if applicable, international financial institutions, must therefore exercise human rights due diligence before implementing farreaching economic reforms that have the potential to undermine the enjoyment of human rights. There is growing international recognition, confirmed by decisions, general comments, concluding observations and statements of human rights mechanisms and academic literature, that potentially retrogressive measures could be regarded as acceptable only if they are: (a) Temporary, in that they remain in place only as long as they are necessary; (b) Legitimate, with the ultimate aim of protecting the totality of human rights; (c) Necessary, in that they must be justifiable after the most careful consideration of all other less restrictive alternatives; (d) Reasonable, in that the means chosen are the most suitable and capable of achieving the legitimate aim; (e) Proportionate, in the sense that, the adoption of any other policy or failure to act would be more detrimental to the enjoyment of economic, social and cultural rights; (f) Not discriminatory and can mitigate the inequalities that can emerge in times of crisis; and they ensure that the rights of disadvantaged and marginalized individuals and groups are not disproportionately affected; (g) Protective of the minimum core content of economic, social and cultural rights; based on transparency and genuine participation of affected groups in examining the proposed measures and alternatives; (h) Subject to meaningful review and accountability procedures. 26 30. Non-discrimination is a core principle of international human rights law and is embodied in all international human rights treaties. In human rights law, discrimination constitutes any distinction, exclusion, restriction or preference or other differential treatment that is based on any ground such as race, colour, sex, language, religion, political or other opinion, national or social origin, property, birth or other status, and which has the purpose or effect of nullifying or impairing the recognition, enjoyment on an equal footing or exercise of all rights and freedoms by all persons. It also includes any action or omission that, whether intended or not, disproportionately affects members of a particular group. In order to eliminate de facto discrimination, States may be under an obligation to take special , 26 See E/C.12/2016/1; Committee on Economic, Social and Cultural Rights, general comment No. 19 (2007) on the right to social security, para. 42; Letter dated 16 May 2012 addressed by the Chairperson of the Committee on Economic, Social and Cultural Rights to States parties to the International Covenant on Economic, Social and Cultural Rights; Aoife Nolan (ed.) Economic and Social Rights After the Global Financial Crisis, (Cambridge, United Kingdom, Cambridge University Press, 2014); and Center for Economic and Social Rights, “Assessing austerity”. 9