What is the difference between void and voidable marriage?

The difference between void and voidable marriage is as follows: 

Void marriage is marriage which is nullity e.g. one in which parties thereto are within prohibited relationships whereas voidable marriage is that marriage which is valid until and unless it is annulled by a decree of the Court e.g. where at the time of marriage either party to the marriage is incapable of consummating it. See section 39(a) (i) of Law of Marriage Act, 1971.