GUWAHATI: Chief minister Sarbananda Sonowal said India needs a “stringent” immigration policy and all states should undergo national register of citizens (NRC) updating process to tackle illegal migration.Speaking at a seminar on “NRC: Defending the Borders, Securing the Culture” organized by Rambhau Mhalgi Prabodhini at the Constitution Club, New Delhi on Monday, Sonowal said NRC is the tool for making the distinction between bona fide citizens and foreigners.The chief minister said large-scale migration has threatened to alter the identity of the Assamese community which is shaped by assimilation of communities.“In 70 years between 1901 and 1971, Assam ’s population increased from 32.90 lakh to 146 lakh, which is 343.77 per cent increase over a period when the population of India had increased by only about 150 per cent and this is clearly the result of illegal migration,” he said.Sonowal said NRC updating process in Assam can be a model to emulate across the country for tackling the problem of illegal migration.“It is imperative to update the NRC in rest of the country to ensure immigrants from Assam do not find shelter in other parts of India. Otherwise, the ongoing exercise in Assam will be a futile one. It does not serve the larger interests of India to cleanse Assam of illegal migrants and then have them resettle in other parts of the country,” Sonowal said.Sonowal said that to plug vulnerable gaps along India's borders, a 'smart fence' project has been rolled out in Assam on a riverine stretch with Bangladesh. The problem of illegal migration can be solved permanently once the border gets completely sealed, he added.The chief minister said genuine Indian citizens will get adequate opportunities to get themselves registered in NRC through the process of claims and objections. He said that the Citizenship Rules provide that any person if not satisfied with the outcome of claims and objections can appeal in the Foreigner’s Tribunal.“ Thus, there is no question of anyone being put in a detention centre after the publication of NRC, as being rumoured by certain vested groups”, Sonowal added.