Citizenship--Part II of the 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.