The Union government told the Supreme Court on Monday that it was not possible to collect accurate data on undocumented immigrants in India, as they enter the country in a “clandestine and surreptitious” manner, The Indian Express reported.

The court had on December 7 told the Centre to state how many foreigners were detected through orders of foreigners tribunals between January 1, 1966 and March 31, 1971. This was in response to petitions challenging the constitutional validity of Section 6A of the Citizenship Act.

Section 6A was introduced as a special provision under the Act when the Assam Accord was signed between the Centre and leaders of the Assam Movement in 1985. It allows foreigners who came to Assam between January 1, 1966, and March 25, 1971, to seek Indian citizenship.

On Monday, Union Home Secretary Ajay Bhalla told the court in an affidavit said that 14,346 foreigners were deported between 2017 and 2022 on account of reasons such overstay, visa violation and illegal entry, according to Bar and Bench.

The affidavit added that 17,861 persons who entered Assam between January 1, 1966, and March 25, 1971 were given citizenship.

On the other hand, 32,381 persons who entered India during the same period have been declared as foreigners by orders of foreigners tribunals until October 31, 2023.

The home secretary’s affidavit said that of the 2,216.7-kilometre border that West Bengal shares with Bangladesh, 78% of it is fenced, while 435.504 kilometres is yet to be fenced. Of this, a stretch of around 286.35 kilometres has not yet been fenced due to delays in land acquisition, he told the court.

“The West Bengal government follows a far slower, more complex direct land purchase policy even for national security projects such as border fencing,” the affidavit alleged. “Due to the non-cooperation from the state government regarding resolving various issues of land acquisition, considerable delays have occurred in acquiring the necessary land, thereby impeding the timely completion of fencing in West Bengal along the Indo-Bangladesh border, which is a vital national security project”.

The government said that Assam shares an approximately 263-kilometre border with Bangladesh, of which about 210 kilometres have been fenced and the remaining length has been covered with technological solutions.

The Supreme Court will hear the matter further on Tuesday.