The Modi government on Tuesday said the National Register of Citizens is a “necessary exercise” for any sovereign country and it would have to carry it out as per the dictates of Indian law. The government made the submissions in an affidavit to the Supreme Court as its response to a batch of petitions challenging the Citizenship Amendment Act.

The government’s legal response comes after a series of flip-flops on the NRC, an exercise to create a list of Indian citizens and hence identify what Indian law called “illegal migrants”. After a year of the ruling Bharatiya Janata Party making the NRC the plank of many election campaigns, Prime Minister Modi had in December claimed that his government was not thinking about the exercise and had, in fact, never spoken about it.

However, Modi’s statement contradicted the Bharatiya Janata Party’s 2019 manifesto that contained a promise to carry out the exercise. The President’s address to Parliament in the same year also included a promise to conduct an NRC. The President’s address is authored by the Cabinet.

In December, the government also approved a budget of Rs 3,900 crore for the creation of the National Population Register, a door-to-door survey that is the first step of the NRC, as laid down in law. The exercise is scheduled to begin in April.

As part of it submission to the Supreme Court, the Modi government has now argued that the NRC is needed to identify illegal migrants. “It is submitted that the preparation of a national register of citizens is a necessary exercise for any sovereign country for mere identification of citizens from non-citizens,” it argued. “It is therefore, the responsibility entrusted on the Central Government, on a combined reading of the Foreigners Act, The Passport (Entry into India) Act, 1920 and the 1955 Act to identify/detect illegal migrants and thereafter, follow the due process of law.”

The passage of the Citizenship Amendment Act in December sparked off widespread protests across India that are still going on. The law puts in a religious filter for Indian citizenship, allowing non-Muslim illegal migrants from Afghanistan, Bangladesh and Pakistan a chance to become Indians. Union Home Minister Amit Shah has at multiple times linked the CAA and the NRC, arguing that the CAA’s religious filter would mean only Muslims would have to undergo the NRC screening test.