ConstitutionofIndia,1949

 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 preceding such commencement, shall be a citizen of India.