Cause
See also: Assam agitationIn 1978 the member of the Lok Sabha, Hiralal Patwari, died necessitating a by-election in the Mangaldoi Lok Sabha Constituency. During the process of the election it was noticed that the electorate had grown phenomenally (allegedly due to illegal immigration). The All Assam Students Union (AASU) demanded that the elections be postponed till the names of "foreign nationals" were deleted from the electoral rolls. The AASU subsequently launched an agitation to compel the government to identify and expel immigrants.
The ethnic clash that took place in Nellie was seen as a fallout of the decision to hold the controversial Assembly elections in 1983 (boycotted by the AASU) despite stiff opposition from several elements in the state. Police officials had suggested to hold the polls in phases in order to avoid violence. According to then Assam Inspector General of Police, KPS Gill, there were 63 constituencies, where elections could have been held without any trouble. Among the rest, the Assam police had declared there were 23 constituencies where it was "impossible to hold any election." Nellie was cited as one of the "troubled" spots before the elections.
400 companies of Central paramilitary force and 11 brigades of the Indian Army were deployed to guard Assam while the polls were scheduled to take place in phases.
Read more about this topic: Nellie Massacre