The National Register of Citizens aims to weed out foreigners living illegally in Assam.

Following a Supreme Court order, the Assam government has decided to release "declared foreigners" languishing in its detention centres for over three years. It has sent notifications in this regard to all six centres of the kind across the state.

But the detainees would have to produce two sureties of Rs 1 lakh each, besides a verifiable address, in order to be set free. Sources in the Assam government said they will also be required to provide biometric information such as fingerprint and iris scans, besides photographs, and report to a police station in their locality every week.

The process will start this week, sources said.

According to the Assam government's replies in the ongoing state assembly session, there are 1,145 declared foreigners lodged in detention centres across Assam. Of them, 335 people are eligible for release as per the Supreme Court order.

The state government also revealed that 25 people who were declared as foreigners have died in detention due to illness. As many as 24 of these deaths occurred in the last three years.

Since 1985, foreigners tribunals have declared 1,17,164 people as foreigners living illegally in Assam. A week ago, the Supreme Court extended the deadline for the final publication of Assam's National Register of Citizens (NRC) list from July 31 to August 31. The exercise, which aims to weed out illegal immigrants in the state, has come in for criticism from rights activists who claim that more than 40 lakh people - many of them legitimate citizens - have been left out of the list so far.

The most prominent among these cases was that of Mohammad Sanaullah, a retired Indian Army soldier who was sent to a detention centre on charges of being a "foreigner" on May 29. The Gauhati High Court ordered his release on bail the next month, and sent notices to the state as well as the central government.

In another incident, Assam authorities went to Chirang district's No.1 Bishnupur village in search of an alleged foreigner identified as Madhubala Das but picked up one Madhubala Mondal instead. She was released on June 27 from the Kokrajhar detention centre, after languishing there for over three years.