4. Conditions relating to solemnization of special marriages.—Notwithstanding anything contained in any other law for the time being in force relating to the solemnization of marriages, a marriage between any two persons may be solemnized under this Act, if at the time of the marriage the following conditions are fulfilled, namely:—
(a) neither party has a spouse living;
1[(b) neither party—
(i) is incapable of giving a valid consent to it in consequence of unsoundness of mind; or
(ii) 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
(iii) has been subject to recurrent attacks of insanity 2[***];]
(c) the male has completed the age of twenty-one years and the female the age of eighteen years;
3[(d) the parties are not within the degrees of prohibited relationship:
Provided that where a custom governing at least one of the parties permits of a marriage between them, such marriage may be solemnized, notwithstanding that they are within the degrees of prohibited relationship; and]
4(e) where the marriage is solemnized in the State of Jammu and Kashmir, both parties are citizens of India domiciled in the territories to which this Act extends].
5[Explanation.—In this section, “custom”, in relation to a person belonging to any tribe, community, group or family, means any rule which the State Government may, by notification in the Official Gazette, specify in this behalf as applicable to members of that tribe, community, group or family:
Provided that no such notification shall be issued in relation to the members of any tribe, community, group or family, unless the State Government is satisfied—
(i) that such rule has been continuously and uniformly observed for a long time among those members;
(ii) that such rule is certain and not unreasonable or opposed to public policy; and
(iii) that such rule, if applicable only to a family, has not been discontinued by the family.]