In which of the following reports, the Law Commission recommended the "Breakdown Principle" to be…

The Law Commission’s Seventy-first Report, submitted in April 1978, specifically considered the Hindu Marriage Act and recommended irretrievable breakdown of marriage as an additional ground for divorce. Its recommendation must be distinguished from Parliament actually adding such a statutory ground.

Current law: Shilpa Sailesh in 2023 confirmed the Supreme Court’s discretionary Article 142 power to dissolve an irretrievably broken marriage, including over a spouse’s opposition, with safeguards. This does not make breakdown a generally available additional ground in an ordinary Hindu Marriage Act divorce court.