law: Passports Act, 1967
  4. Classes of passports and travel documents
  (1) The following classes of passports may be
  
  issued under this Act, namely: -
  (a) ordinary passport;
  (b) official passport;
  (c) diplomatic
  
  passport.
  (2) The following classes of travel documents
  
  may be issued under this Act, namely:
  (a) emergency
  
  certificate authorizing a person to enter India;
  (b) certificate of
  
  identity for the purpose of establishing the identity of person;
  (c) such other
  
  certificate or document as may be prescribed.
  (3) The Central Government shall, in
  
  consonance with the usage and practice followed by it in this behalf, prescribe
  
  the classes of persons to whom the classes of passports and travel documents
  
  referred to respectively in sub-section (1) and sub-section (2) may be issued
  
  under this Act.