Section 5 in The Hindu Marriage Act, 1955
5 Conditions for a Hindu marriage. 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 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
(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 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;
(i) A marriage between a Hindu man who converted as Christian and a Christian lady in a Hindu form is not a valid marriage. According to section 5 of the Act marriage can be solemnized between two Hindus; M. Vijayakumari v. K. Devabalan, AIR 2003 Ker 363.
(ii) To draw an inference merely from the fact that the spouses had no co-habitation for a short period of about a month, is neither reasonable nor permissible. To brand the wife as unfit for marriage and procreation of children on account of the mental disorder, it needs to be established that the ailment suffered by her is of such a kind or such an extent that it is impossible for her to lead a normal married life; R. Lakshmi Narayan v. Santhi, AIR 2001 SC 2110.