Foreign Marriage Act, 1969
contains the law, which governs the marriages of citizens of India outside
India.
To put it simple it applies to a person, who is an Indian citizen but is living in Foreign Country [or on a foreign ship, which is in the territorial waters outside of India], wants to marry an Indian or a foreigner there at the foreign land.
Foreign Marriage Act, 1969 came into effect on 31st August, 1969
See preamble of the Foreign Marriage Act, 1969