33 Therefore, on the date on which, according to the referring court, the merits of the action before it must be examined, namely that of the decision to revoke the assurance as to the grant of Austrian nationality, JY had already become stateless and, therefore, had lost her status of citizen of the Union. 34 That court and the Austrian Government conclude that the situation at issue in the main proceedings does not fall within the scope of EU law and state in that respect that that situation is different from those which gave rise to the judgments of 2 March 2010, Rottmann (C‑135/08, EU:C:2010:104), and of 12 March 2019, Tjebbes and Others (C‑221/17, EU:C:2019:189). 35 However, it is important, in the first place, to note that, in a situation such as that of JY, although the loss of the status of citizen of the Union stems from the fact that the Member State of origin of that person, at that person’s request, has dissolved the bond of nationality with the latter, that application was made in the context of a naturalisation procedure seeking to obtain Austrian nationality and is the consequence of the fact that that person, taking account of the assurance given to him or her that he or she will be granted Austrian nationality, complied with the requirements of both the StbG and the decision concerning that assurance. 36 In those circumstances, a person such as JY could not be considered to have renounced voluntarily the status of citizen of the Union. On the contrary, having received from the host Member State the assurance that he or she will be granted the nationality of the latter, the purpose of the application for dissolution of the bond of nationality with the Member State of which that person is a national is to enable that person to fulfil a condition for the acquisition of that nationality and, once obtained, to continue to enjoy the status of citizen of the Union and the rights attaching thereto. 37 In the second place, it must be noted that it is for each Member State, having due regard to international law, to lay down the conditions for acquisition and loss of nationality, and that in situations covered by EU law, the national rules concerned must have due regard to the latter (judgment of 14 December 2021, V.М.А., C‑490/20, EU:C:2021:1008, paragraph 38 and the case-law cited). 38 In addition, Article 20(1) TFEU confers on every person holding the nationality of a Member State Union citizenship, which, according to settled case-law, is destined to be the fundamental status of nationals of the Member States (judgment of 15 July 2021, A (Public healthcare), C‑535/19, EU:C:2021:595, paragraph 41 and the case-law cited). 39 Where, in the context of a naturalisation procedure, the competent authorities of the host Member State revoke the assurance as to the grant of nationality of that State, the person concerned who was a national of one other Member State only and renounced his or her original nationality in order to comply with the requirements of that procedure is in a situation in which it is impossible for that person to continue to assert the rights arising from the status of citizen of the Union. 40 Consequently, such a procedure, taken as a whole, even if it involves an administrative decision of a Member State other than that of which nationality is sought, affects the status conferred by Article 20 TFEU on nationals of the Member States, since it may result in a person in a situation such as that of JY being deprived of all the rights attaching to that status, although, at the time when the naturalisation procedure began, that person held the nationality of a Member State and thus had the status of citizen of the Union. 41 In the third place, it is common ground that JY, as an Estonian national, has exercised her freedom of movement and residence, pursuant to Article 21(1) TFEU, by settling in Austria, where she has been living for several years. 42 However, the Court has already held that the rights conferred on a Union citizen by Article 21(1) TFEU are intended, amongst other things, to promote the gradual integration of the Union citizen concerned in the society of the host Member State (judgment of 14 November 2017, Lounes, C‑165/16, EU:C:2017:862, paragraph 56). 43 Thus, the underlying logic of gradual integration that informs that provision of the FEU Treaty requires that the situation of citizens of the Union, who acquired rights under that provision as a result of having exercised their right to free movement within the European Union and are liable to lose not only