In 1978,
Lok Sabha member 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. Investigation revealed that there had been mass inclusion of alleged illegal migrants. The
All Assam Students Union (AASU) demanded that the elections be postponed until 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 allegedly illegal immigrants. The
central government attempted to placate the
Assamese by agreeing to proscribe any migrants who entered the state after March 1971 from voting, and proceeded with the elections. The Assamese, demanding an earlier cutoff date, were inimical to the government's decision, as were the
Lalung (Tiwa) tribals who resented the proliferation of Bengali immigrants onto their land. Conversely, the Bengali communities (both Hindu and Muslim) as well as the
Plains Tribal Council of Assam, an organization composed exclusively of
Boro tribals opposed to Assamese hegemony, supported the elections, and subsequent inter-ethnic violence unfolded. 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. ==Vajpayee's Comments==