At least 70,000 declared illegal migrants in Assam have vanished before they could be deported back.

The Assam government, in its affidavit to the Supreme Court, has admitted that 70,000 individuals who were declared foreigners by the tribunal are untraceable now. "They have mixed with the local population," Solicitor General Tushar Mehta submitted before a bench headed by Chief Justice of India Ranjan Gogoi.

According to Mehta, the tribunals had determined them foreigners but before they could be sent back, they "merged" with the locals in the state.

The state government’s submission irked the top court, which wondered if declared foreigners could vanish like this, what would happen to those whose proceedings are yet to be finalised by the foreigner's tribunal.

The bench also pulled up the state for not having its chief secretary present in the court despite its order. "There has to be a reason why we wanted the chief secretary to remain present. But he is not here. Should we issue a non-bailable warrant against him?” the CJI asked Mehta.

As Mehta undertook to make him available on the next date of hearing, the bench ordered that the chief secretary will remain present on Monday next and will not go back to Assam until allowed by the court.

"Your government is playing around with the orders of this court. Your affidavit is an exercise in futility. Despite all your non-cooperation, we can pass orders under our constitutional powers. Should we do that?" the bench asked the SG.

Mehta, on his part, requested the bench to hear the state on this aspect and assured that the state was doing its best to deal with the problem of illegal migrants in Assam.

At one point, the CJI also took note of the submission by Mehta that a "push back" policy was being followed till 2013. "So what happened now? Have you become wiser?" retorted the bench.

On an earlier date, the bench had sought statistics from the Assam government on number of illegal migrants declared foreigners and those deported.