Six months waiting period in divorce by mutual consent is NOT mandatory. This was held in _______.

In "Amardeep Singh vs Harveen Kaur" (2017), the Supreme Court held that the six-month period in Section 13B(2) of the Hindu Marriage Act, 1955 is directory, not mandatory, and the court may waive it in suitable cases. The court considers factors such as whether the parties have already been separated for more than the combined period of one year and six months, whether efforts at mediation or reconciliation have failed, and whether the parties have settled their differences, including alimony and custody. The other cases listed did not lay down this rule.