The Constitution of India provides for a single citizenship for the whole of India. Every person who was at the commencement of the Constitution (26 January 1950) domiciled in the territory of India, and (a) who was born in India, or (b) either of whose parents was born in India, or (c) who has been ordinarily resident in India for not less than five years, became a citizen of India. The Citizenship Act, 1955 deals with matters relating to acquisition, determination and termination of Indian citizenship after the commencement of the Constitution.

Source: India Book 2020 - A Reference Annual