The centre has indicated that they may consider a national citizens register (NRC) for the entire country, an extension of the contentious citizenship excercise underway in Assam.
This, they say, is necessary to weed out illegal Bangladesh infiltrators, portrayed as a large-scale problem.
But the government's own claims on illegal immigrants in the country is mired in conflicting numbers and denials, NDTV has found.
The only two times that a number was placed on record was in 2004, when the then Minister of State for Home Sriprakash Jaiswal told parliament that there were 1.2 crore illegal Bangladeshis residing in India, a statement he later retracted, claiming the number came from 'hearsay' and 'interested parties'.
The second time was in 2016, when Mr Jaiswal's successor, Kiren Rijiju, told parliament that the number was close to 2 crores, a jump of nearly 70 per cent over Mr Jaiswal's figure. Mr Rijiju did not cite the source of the data.
But on at least seven instances in the past four years, the government has conceded that it has no evidence on the number of illegal immigrants.
The phrasing of the denials over the years sounds the same. In the first such denial, in April 2017, the Home Ministry told parliament that it is "not possible to have accurate data of Bangladeshi Nationals living in country".
In 2017 alone, there were three instances from December, August and March where the government said that there was no accurate data available on illegal immigrants. "Since entry of Bangladeshi nationals into the country is clandestine, accurate data of such cases is not available," the government said in its reply in March that year.
NDTV found three more instances from December 2016, December 2015 and April 2015 where the government said that it wasn't "possible to have accurate data of Bangladeshi nationals living in the country".