Indian Constitution - part4 (Acquiring Citizenship)

The citizenship can be acquired by birth, by descent or by naturalization. Except in the case of children born in India to foreign diplomats accredited to this country or to enemy aliens, every person born in India on or after the 26th of January, 1950, is a citizen of India by birth.

A person born outside India on or after the 26th of January, 1950, is a citizen of  India by descent if his or her father happened to be citizen of India at the time of his or her birth. Citizenship can be acquired by naturalisation by persons of Indian origin ordinarily living outside India and Pakistan, by women married to citizens of India, by persons belonging to other countries who fulfil certain conditions laid down in citizenship Act of 1955.

single citizenship