law: Special Marriage Act, 1954 
  4. Conditions relating to solemnization
  
  of special marriages
  Notwithstanding
  
  anything contained in any other law for the time being in force relating to be solemnization
  
  of marriages, a marriage between any tow 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;
   9  [(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 or epilepsy;]
  (c) the male has
  
  completed the age of twenty-one years and the female the age of eighteen years;
   10  [(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]
   11  [(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.]
   12  [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 issue 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.]