15. Registration of marriages celebrated in other forms.- Any marriage celebrated, whether before or after the commencement of this Act, other than a marriage solemnized under the
1[ Special Marriage Act, 1872 , (3 of 1872 ) or under this Act, may be registered under this Chapter by a Marriage Officer in the territories to which this Act extends if the following conditions are fulfilled, namely:-
a ceremony of marriage has been performed between the parties and they have been living together as husband and wife ever since;
neither party has at the time of registration more than one spouse living;
neither party is an idiot or a lunatic at the time of registration;
the parties have completed the age of twenty- one years at the time of registration;
the parties are not within the degrees of prohibited relationship: Provided that in the case of a marriage celebrated before the commencement of this Act, this condition shall be subject to any law, custom or usage having the force of law governing each of them which permits of a marriage between the two; and
the parties have been residing within the district of the Marriage Officer for a period of not less than thirty days immediately preceding the date on which the application is made to him for registration of the marriage.