The Assam Movement (or Assam Agitation) (1979-1985) was a popular movement against illegal immigrants in Assam. The movement, led by All Assam Students Union (AASU) and the 'All Assam Gana Sangram Parishad' (AAGSP), developed a program of protests and demonstration to compel the government to identify and expel illegal immigrants. The agitation programs were largely non-violent, but the Nellie massacre was a case of extreme violence. The agitation program ended in August 1985 following the Assam Accord, which was signed by leaders of AASU-AAGSP and the Government of India.
The agitation leaders formed a political party, Assam Gana Parishad. It came to power in the state of Assam in the Assembly elections of 1985 and later in 1996.
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.
On 27 November 1979, AASU-AAGSP combine called for the closure of all educational institutes and picketing in state and central government offices. Mass picketing was arranged in front of all polling offices where candidate nominations could be filed, in the first week of December 1979. No candidates were allowed to file nomination papers in the Brahmaputra valley. December 10, the last date for submitting the nomination papers, was declared as a statewide bandh. The government proclaimed a curfew at different parts of the state, including the major city of Guwahati.
At Barrpeta, then IGP K.P.S. Gill led the police force in escorting Bagam Abida Ahmed to file nomination papers; they attacked protestors. Khargeswar Talukdar, the 22-year-old general secretary of Barpeta AASU Unit, was beaten to death and thrown into a ditch next to the highway at Bhabanipur. Talukdar has been honoured by the Assam Movement as its first Martyr.