A/CONF.189/PC.2/22 page 15 paragraph 1). Clearly, then, it is not only the State that has obligations regarding the content of education, but all who occupy positions of responsibility within a country’s educational system.46 47. The second aspect relates to the standard of education provided in these establishments, which should “conform to such minimum educational standards as may be laid down or approved by the State”.47 The yardstick here is the standard of education provided in public institutions as regards, for example, admission, curricula and the recognition of certificates (see General Comment No. 13, E/C.12/1999/10, para. 30). Failure to comply with this principle may constitute prohibited discrimination.48 48. The third aspect emerges by converse implication from article 2 (c) of the 1960 UNESCO Convention, concerning non-discriminatory situations. The aim of establishing or maintaining this type of education must not be “to secure the exclusion of any group but to provide educational facilities in addition to those provided by the public authorities”.49 Private schools therefore complement public education in cases where the public system does not provide teaching of or in the language and of the religion of an ethnic or religious minority. (b) Freedom of education, religious education and religious intolerance 49. In many instruments, religious education is seen as a projection of freedom of conscience, which is itself the basis of freedom of education.50 That explains why the reference to religious education is encapsulated within provisions on educational freedom. The most comprehensive provision in that regard is article 5, paragraph 1 (b), of the 1960 UNESCO Convention, which reads: “It is essential to respect the liberty of parents …, secondly, to ensure in a manner consistent with the procedures followed in the State for the application of its legislation, the religious and moral education of the children in conformity with their own convictions; and no person or group of persons should be compelled to receive religious instruction inconsistent with his or their convictions”.51 Accordingly, the principle of non-discrimination implies in this case two distinct kinds of obligation falling upon the State. 50. The first, purely passive obligation (that of non-interference), deriving from the implementation of educational pluralism, is that of respect for the liberty of parents practising minority religions to choose for their children private institutions offering an education in conformity with their convictions, provided that the instruction given meets minimum quality standards. 51. The second obligation seems to concern public establishments52 and lays upon the State two requirements of widely varying stringency. Firstly, the State is required to take the necessary measures, through appropriate modalities of implementation, to provide within its own educational system for the religious education of children in accordance with their parents’ convictions and therefore those of minority religious groups.53 The wording of article 5, paragraph 1 (b), of the 1960 UNESCO Convention does not state what modalities are meant: