Citizenship Act, 1955
13. Certificate of citizenship in case of doubt
The Central Government may, in such cases as it thinks fit,
certify that a person with respect to whose citizenship of India a doubt
exists, is a citizen of India; and a certificate issued under this section
shall, unless it is proved that it was obtained by means of fraud, false
representation or concealment of any material fact, be conclusive evidence that
that person was such a citizen on the date thereof, but without prejudice to
any evidence that he was such a citizen at an earlier date.