Citizenship Act, 1955
5. Citizenship by registration
(1) Subject to the provisions of this section and such conditions and restrictions as may be prescribed, the prescribed authority may, on application made in this behalf, register as a citizen of India any person who is not already such citizen by virtue of the Constitution or by virtue of any of the other provisions of this Act and belongs to any of the following categories,-
(a) persons of Indian origin who are ordinarily resident in India and have been resident for five years immediately before making an application for registration;
(b) persons of Indian origin who are ordinarily resident in any country or place outside undivided India;
(c) persons who are, or have been, married to citizens of India and are ordinarily resident in India and have been so resident for five years immediately before making an application for registration.
(d) minor children of persons who are citizens of India; and
(e) persons of full age and capacity who are citizens of a country specified in Schedule I:
PROVIDED that in prescribing the conditions and restrictions subject to which persons of any such country may be registered as citizens of India under this clause, the Central Government shall have due regard to the conditions subject to which citizens of India may, by law or practice of that country, become citizens of that country by registration.
Explanation : For the purposes of this sub-section, a person shall be deemed to be of Indian origin if he, or either of his parents, was born in undivided India.
(2) No person being of full age shall be registered as a citizen of India under sub-section (1) until he has taken the oath of allegiance in the form specified in Schedule II.
(3) No person who has renounced, or has been deprived of his, Indian citizenship, or whose Indian citizenship has terminated, under this Act shall be registered as a citizen of India under sub-section (1) except by order of the Central Government.
(4) The Central Government may, if satisfied that there are special circumstances justifying such registration, cause any minor to be registered as a citizen of India.
(5) A person registered under this section shall be a citizen of India by registration as from the date on which he is so registered; and a person registered under the provisions of clause (b)(ii) of Article 6 or Article 8 of the Constitution shall be deemed to be a citizen of India by registration as from the commencement of the Constitution or the date on which he was so registered, whichever may be later.