HINDU MARRIAGES : Sec 5.

5. A marriage may be solemnized between any two Hindus, if the following conditions are fulfilled, namely:- (i) Neither party has a spouse living at the time of the marriage
(ii) At the time of the marriage, neither party-
(a) is incapable of giving a valid consent to it in consequence of unsoundness of mind; or
(b) Though capable of giving a valid consent, has been suffering from mental disorder of such a kind or to such an extent as to be unfit for marriage and the procreation of children; or
(c) Has been subject to recurrent attacks of insanity or epilepsy;
(iii) The bridegroom has completed the age of twenty- one years and the bride the age of eighteen years at the time of the marriage;
(iv) The parties are not within the degrees of prohibited relationship unless the custom or usage governing each of them permits of a marriage between the two;
(v) The parties are not sapindas of each other, unless the custom or usage governing each of them permits of a marriage between the two.