Under the Hindu Marriage Act, 1955 (in the absence of any governing custom or usage to the contrary),…

Under Section 3(g)(iii) of the Hindu Marriage Act, 1955, two persons are said to be within the 'degrees of prohibited relationship' if one was the wife of the brother of the other. Under Section 5(iv) read with Section 11 of the Act, a marriage solemnized between two Hindus who are within the degrees of prohibited relationship is null and void (unless the custom or usage governing each of them permits a marriage between the two).