The Illegal Migrant Act of India, 1983

The Illegal Migrants (Determination by Tribunals) Act, 1983 (IMDT Act) was a law enacted by the Indian Parliament specifically for the state of Assam to detect and deport illegal immigrants, particularly those from Bangladesh. It was introduced in response to the growing concerns during the Assam Movement, which arose due to large-scale migration from Bangladesh following the 1971 Liberation War. Unlike the Foreigners Act, 1946—applicable to the rest of India—the IMDT Act applied only to Assam and defined an illegal migrant as anyone who entered India on or after March 25, 1971, without valid documents. One of the Act's most controversial features was that it placed the burden of proof on the complainant or the authorities, rather than the suspected illegal migrant. It established special tribunals to handle such cases, but these were often criticized for inefficiency and leniency. The Act was widely condemned in Assam for making the detection and deportation of illegal immigrants difficult, thereby threatening the state’s demographic balance. In 2005, the Supreme Court of India struck down the IMDT Act as unconstitutional in the landmark Sarbananda Sonowal v. Union of India case, stating that the Act had become the main obstacle in identifying and removing illegal migrants. Following its repeal, Assam came under the purview of the Foreigners Act, 1946, which shifted the burden of proof onto the suspected person and allowed stricter action against illegal immigration, eventually contributing to the implementation of the National Register of Citizens (NRC) in the state.