The concern for rapidly increasing amount of refugees arriving from East Bengal and later newly formed East Pakistan in the 1940s , created tension among the Indigenous Assamese people and many tribes in the state . The first influx of Hindu refugees in considerable number was in October 1946 following the Noakhali riots . Between 1948 and 1971 , there were large scale migrations from Bangladesh ( then East Pakistan ) to Assam . By May 1949 the number of total immigrants reached two-and-half lakhs , increasing up to 2,74,455 . Given this continuing influx of illegal migrants from Bangladesh into Assam , student leaders in 1979 came out in fierce protest demanding detention , disenfranchisement and deportation of illegal immigrants from Assam . In 1978 Hiralal Patwari died , requiring a by-election in the Mangaldoi Lok Sabha Constituency to fill his seat . During the process of the election , observers noticed that the number of registered voters had grown dramatically . AASU demanded that the elections be postponed till the names of foreign nationals were deleted from the electoral rolls . The Assam Agitation developed from there
Noakhali riots
Noakhali riots
Assam Movement