During the Golap Barbara Ministry (March 1978-August 1979), emergence of students .union became prominent. All Assam-'Students’ Union or AASU was the strongest organisation and their main demand was deportation of foreigners from Assam. 

AASU spearheaded the movement against undocumented immigrants in Assam. When Hiralal Patwari died in 1978 and a by-election was required in Mangaldoi Lok Sabha Constituency to fill his seat, it was realised that there was a substantial increase in number of registered voters. 

AASU wanted the names of foreign nationals to be identified and deleted from electoral rolls. Therefore, they demanded for the elections to be postponed. This initiated Assam Agitation or the Assam Movement (1979-1985). 

The AASU and All Assam Gana Sangram Parishad (AAGSP) developed a strategy of protests and demonstrations to force the government to identify and deport the illegal immigrants. 

The two groups together on 27 November 1979, called for the closure of all educational institutes, and picketing began in state and central government offices. Filing of nomination papers for the elections was stopped in the Brahmaputra Valley. A statewide bandh was declared on the last date of filing the nomination papers. 

Though the agitation was mostly peaceful and non-violent, there was a massacre in Nellie and it turned violent. 

The government introduced curfew in many parts of the state, including Guwahati. As a result, Illegal Immigrants Act was passed in October 1983.