Constitution Of India Article 5 - Citizenship at the commencement of the Constitution
At the commencement of this Constitution, every person who has his domicile in the territory of India and:
(a) who was born in the territory of India; or
(b) either of whose parents was born in the territory of India; or
(c) who has been ordinarily resident in the territory of India for not less than five years immediately preceding such commencement,
shall be a citizen of India.