India's controversial religion-based citizenship act will have to pass the scrutiny of the nation's top court, even as Prime Minister Narendra Modi's government pledged to push ahead and implement the law.

A three-judge bench headed by Chief Justice of India S.A. Bobde issued a notice to the government seeking its response. The court agreed to examine the legality of the legislation following more than 50 petitions filed by activists, lawyers, student groups, Muslim bodies, and politicians from across the country. The court will next hear the case on Jan. 22 and may decide in January if the law should be stayed, Bobde said.

The move may calm protesters who have called the law discriminatory because it bars undocumented Muslims from Pakistan, Afghanistan and Bangladesh from seeking citizenship but allows Hindus, Sikhs, Buddhists, Jains, Parsis and Christians who migrated from these regions to do so. On Tuesday, Home Minister Amit Shah, who shepherded the Citizenship Amendment Act through the Parliament last week, defended it and ruled out any possibility of repealing the law.