Rules for Indian marriages:
A marriage which has already been solemnised can be registered either under the Hindu Marriage Act, 1955 or under the Special Marriage Act, 1954.
The Hindu Marriage Act is applicable in cases where both husband and wife are Hindus, Buddhists, Jains or Sikhs or where they have converted into any of these religions. Where either of the husband or wife or both are not Hindus, Buddhists, Jains or Sikhs the marriage is registered under the Special Marriage Act, 1954.
Further, marriage can be solemnised between any two persons under the provisions of the Special Marriage Act, 1954.