The rise of self-determination and Bengali nationalism movements in East Bengal , led by Mujibur Rahman , culminated in the 1971 Bangladesh Liberation War against the Pakistani military junta . An estimated 3 million ( 3,000,000 ) people died in the conflict , particularly as a result of the 1971 Bangladesh genocide . The war caused millions of East Pakistani refugees to take shelter in India 's Bengali state West Bengal , with Calcutta , the capital of West Bengal province , becoming the capital-in-exile of the Provisional Government of Bangladesh . The Mukti Bahini guerrilla forces waged a nine-month war against the Pakistani military . The conflict ended after the Indian Armed Forces intervened on the side of Bangladeshi forces in the final two weeks of the war , which ended with the Surrender of Pakistan and the liberation of Dhaka on 16 December 1971
1971 Bangladesh genocide
1971 Bangladesh genocide
Bengalis