law: 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.