It was the consequence of political, social as well as economic disparity between both the wings of pakistan. Politically eastern pakistan was deprived from leadership of the country, despite its overwhelming majority of the population. western pakistan was economically well-off, as it was the industrial area since the age of british colonialization, and government further gave due attention to this wing for econmic progress while ignoring the eastern part, last but not the least factor was social disparity...e.g. issue of language.

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Self-confidence is the first requisite to great undertakings.