Which of the following is not a ground for divorce under Sec. 13 of the Hindu Marriage Act, 1955?

Non-venereal disease is not a ground for divorce under Section 13 of the Hindu Marriage Act, 1955, as Section 13(1)(v) makes only a venereal disease in a communicable form a statutory ground for divorce. By contrast, cruelty (Section 13(1)(ia)), ceasing to be a Hindu by conversion to another religion (Section 13(1)(ii)), and incurable unsoundness of mind (Section 13(1)(iii)) are express grounds for divorce under Section 13(1).