The Supreme Court on Wednesday said that Section 497 of the Indian Penal Code, which criminalises adultery, is unconstitutional.
"Adultery can be ground for divorce, but not a criminal offence," said Chief Justice Dipak Misra, while reading out the judgement.
Section 497 is "absolutely, manifestly arbitrary", said Misra, reported legal website Live Law.
This judgement is the latest in a series of important verdicts the Supreme Court is delivering this week, CJI Misra's last in office.
On Wednesday, the court ruled that the Aadhaar project is constitutional.