A/CONF.189/PC.2/22 page 22 more complex and certainly more subtle forms. As one study points out: “The ways in which racism manifests itself and is perpetrated vary across cultures, contexts and historical eras - as must the strategies to combat racism”.72 What needs to be done in this area, therefore, will be all the more difficult in that racism has a considerable capacity for adaptation and this scourge cannot reasonably be expected to disappear in the near future. Continuity in the obligation of non-discrimination 72. All the instruments studied reveal a continuity and great consistency in the imperative nature of the obligation relating to the non-discriminatory content of education. This obligation has a dual foundation: (a) Firstly, the general obligation of non-discrimination set out in numerous instruments adopted since the Universal Declaration of 1948. Restrictions on this obligation, including affirmative action, are subject to strict conditions and do not in any way undermine the obligatory nature of the principle.73 Reservations to some of these instruments relating specifically to the struggle against discrimination are either heavily circumscribed74 or prohibited altogether.75 (b) Secondly, as has been pointed out in recent studies, there is no doubt as to the nature of the obligations relating to the content and objectives of education.76 Three important examples deserve to be mentioned: (i) “States Parties undertake to adopt immediate and effective measures …” (article 7 of the International Convention on the Elimination of All Forms of Racial Discrimination); (ii) “The States Parties … agree that education shall be directed …” (article 13, paragraph 1, of the International Covenant on Economic, Social and Cultural Rights and article 29, paragraph 1, of the Convention on the Rights of the Child); (iii) “States Parties shall take all appropriate measures …” (article 10 of the Convention on the Elimination of All Forms of Discrimination against Women); 73. We may add to these examples77 article 5, paragraph 1 (a), of the 1960 UNESCO Convention, which adopts the same imperative wording as does article 26, paragraph 2, of the Universal Declaration: “Education shall be directed to …, it shall promote …”. Such wording is also used in respect of religious education - this is the case with article 5, paragraph 1 (b), of the same instrument: “… no person or group of persons should be compelled to receive religious instruction inconsistent with his or their conviction”. This is likewise true of certain instruments which, although they do not have a fundamentally binding quality, refer to principles already set out in existing international conventions; article 5, paragraphs 2 and 3, of the Declaration on the Elimination of All Forms of Intolerance and of Discrimination Based on Religion or Belief states that: the child “shall not be compelled to receive teaching on religion or belief against the wishes of his parents or legal guardians …” and that the child “shall be brought up in a spirit of understanding, tolerance …”.78