met. The exhaustive nature of the list of possible requirements means that States cannot establish conditions for the grant of nationality additional to those stipulated in the Convention. As a result, providing for a discretionary naturalization procedure for otherwise stateless children is not permissible under the 1961 Convention. A State may choose not to apply any of the permitted conditions and simply grant nationality upon submission of an application.201 The 1961 Convention does not permit States Parties to impose any requirement on an otherwise stateless child born within its territory relating to the child’s parent(s)’ period of residency. Article 1(2)(b) permits a State to require that “a person concerned has habitually resided in the territory of the Contracting State for such period as may be fixed by that State, not exceeding five years immediately preceding the lodging of the application nor ten years in all” (emphasis added). Hence, the habitual residence exception can only be imposed on the person concerned, i.e. on the otherwise stateless applicant seeking citizenship. Article 1(2)(a) permits a State Party to set a fixed period for application for citizenship by otherwise stateless children born within its territory. According to this article, a State can require: that the application is lodged during a period, fixed by the Contracting State, beginning not later than at the age of eighteen years and ending not earlier than at the age of twenty-one years, so, however, that the person concerned shall be allowed at least one year during which he may himself make the application without having to obtain legal authorization to do so.202 Hence, a State that opts for an application procedure pursuant to Article 1(1)(b) must allow an otherwise stateless child born in its territory to apply for citizenship beginning no later than his or her 18th birthday. In other words, it is preferable that such a child be allowed to apply before attaining the age of 18, but in no circumstances may he or she be prevented from applying once the person has attained that age. Moreover, the application period must not end prior to the individual’s attaining the age of 21. In countries where the age of majority is 18, this means that there must be a three-year window of opportunity in which to apply. The clause providing that “the person concerned shall be allowed at least one year during which he may himself make the application without having to obtain legal authorization to do so” should be understood to take account of States that have a higher age of majority or certain situations where the law has recently changed and left certain age groups unintentionally unprotected. Where States change their laws or practice to provide a path to citizenship for otherwise stateless persons born in their territory, UNHCR recommends that the changes be retroactive.203 The importance of a child’s obtaining a nationality is reiterated by Article 7 of the CRC and Article 24 of the ICCPR, the latter of which has been described in the UN Human Rights Committee General Comment No. 17 as follows: “States are required to adopt every appropriate measure, both internally and in cooperation with other States, to ensure that every child has a nationality when he is born.”204 It follows from these articles, and Article 3 of the CRC, which sets out the principle of the best interests of the child, that a child may not be left stateless for an extended period of time.205 Specifically, when read with Article 1 of the 1961 201 UNHCR, Interpreting the 1961 Statelessness Convention and Preventing Statelessness among Children (“Dakar Conclusions”), September 2011, para. 26, available at: http://www.refworld.org/docid/4e8423a72.html. 202 Article 1(2)(a) of the 1961 Convention. 203 See, e.g., Comments by the UNHCR Regional Representation for Northern Europe on the draft Law Proposal amending the Estonian Citizenship Act, para. 22 (May 2014) (“UNHCR recommends that provisions granting Estonian citizenship by birth to children born in Estonia would be applicable retroactively”), available at: http://goo.gl/ZV5mKH. The same recommendation is made in comments by UNHCR to the Legislative Proposal amending the Citizenship Law (Nr. 52/Lp11) in Latvia, p. 2, available at: http://www.refworld.org/docid/57ed07954.html. 204 UN Human Rights Committee (HRC), CCPR General Comment No. 17: Article 24 (Rights of the Child), 7 April 1989, para. 8, available at: http://www.refworld.org/docid/45139b464.html. 205 UNHCR, Guidelines, para. 11. UNHCR STOCKHOLM, 2016 59