India's top court has ruled that adultery is no longer a crime, declaring the colonial-era law that punished the offence unconstitutional and discriminatory.

The court ruled unanimously on Thursday that Section 497, a 158-year-old law, "perpetuates the subordinate status of women, denies dignity and sexual autonomy, and is based on gender stereotypes".

The law criminalised consensual sexual relations between a man and a married woman without the consent of her husband.

Under the law, a man convicted could have faced up to five years in prison and women could neither file a complaint nor be held liable for adultery.

Section 497 has been criticised by rights groups for depriving women of dignity and individual choice, and treating them as the property of men.

"Adultery can be grounds for civil issues including dissolution of marriage but it cannot be a criminal offence ... adultery might not be the cause of an unhappy marriage, it could be the result of an unhappy marriage," said Chief Justice Misra while reading out the verdict.

The judges deemed the law unconstitutional after Indian businessman Joseph Shine filed a petition last year challenging Section 497.

The Indian government had opposed the decriminalisation of adultery, stating in court earlier that this would erode "the sanctity of marriage and the fabric of society at large".

But women's rights campaigners welcomed the ruling on Thursday.

"Scrapping it was long overdue and is very welcome," Kavita Krishnan, secretary of the All India Progressive Women's Association, told Al Jazeera.

"Our political class should have decriminalised adultery and homosexuality a long time ago, instead of leaving it to the courts."

Despite a string of recent liberal-progressive rulings from India's Supreme Court, including the decriminalisation of gay sex, India's conservative and patriarchal attitudes are deeply entrenched.

"This is precisely why political parties and governments pass the buck to courts," said Krishnan.

India is still struggling to balance its deep-rooted traditions with rapid modernisation. (Aljazeera)

Update news