5. Some human rights treaties go even further and expressly require positive action on the part of States to eliminate discrimination on prohibited grounds.119 However, certain treaties protect equality only in the enjoyment of identified substantive rights (commonly described as ‘ancillary’ protection). 120 This means that instead of a free standing right to equality, protection against discrimination is available only in relation to the application of the other rights protected by the relevant treaty. This can have the effect of making equality and non-discrimination more marginal. 6. It is generally understood that mere formal equality – that is a requirement that there be no difference in treatment as between persons in like situations (or ‘direct discrimination’) - is not sufficient to guarantee real equality. Simple equality of treatment, without regard to the differences between the persons or groups of persons concerned, may operate so as to entrench existing disadvantages. Thus, a prohibition on wearing head gear at work imposed on all employees is, formally speaking, equal treatment (so long as no exceptions are made) but can readily be seen as disadvantaging those groups for whom the wearing of head gear might have some religious or cultural significance. 7. The Human Rights Committee has interpreted ‘discrimination’ to mean ‘any distinction, exclusion, restriction or preference which 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 or exercise of all persons, on an equal footing, of all rights and freedoms’.121 Also included among the prohibited grounds in Article 2 ICCPR are sexual orientation and gender identity.122 The concept of ‘other status’ has been given a broad meaning to include not just intrinsically personal qualities but also other such as marital professional and financial status.123 Protecting Against Indirect Discrimination 8. Protection against ‘indirect’ discrimination provides a better opportunity to challenge entrenched discrimination arising out of structural factors. Indirect discrimination is perhaps best explained by a policy, rule or practice that is essentially neutral on its face, in that in theory it applies to everyone, which, however, may be indirectly discriminatory if it has a disparate impact on people belonging to a particular group. 119 Examples include the International Convention on the Elimination of All Forms of Discrimination (CERD) and the Convention on the Elimination of All Forms of Discrimination against Women (CEDAW). 120 E.g. Article 2(2) ICESCR, Article 14 ECHR. 121 General Comment No.18, HRI/GEN/1/Rev.9 (Vol. I) p.195 (1989), para 7. 122 Communication No.488/1992, Toonen v Australia, 31 March 1994; Concluding Observations on Kuwait, CCPR/C/KWT/CO/2. 123 E.g. European Court, Rasmussen v Denmark, 28 November 1984; Van der Mussele v Belgium, 23 November 1983. 41