The India–Pakistan war of 1971, also known as the third Indo-Pakistani war, was a military confrontation between India and Pakistan that occurred during the Bangladesh Liberation War in East Pakistan from 3 December 1971 until the Pakistani capitulation in Dhaka on 16 December 1971. The war began with Pakistan's Operation Chengiz Khan, consisting of preemptive aerial strikes on eight Indian air stations. The strikes led to India declaring war on Pakistan, marking their entry into the war for East Pakistan's independence, on the side of Bengali nationalist forces. India's entry expanded the existing conflict with Indian and Pakistani forces engaging on both the eastern and western fronts.
Thirteen days after the war started, India achieved a clear upper hand, and the Eastern Command of the Pakistan military signed the instrument of surrender on 16 December 1971 in Dhaka, marking the formation of East Pakistan as the new nation of Bangladesh. Approximately 93,000 Pakistani servicemen were taken prisoner by the Indian Army, which included 79,676 to 81,000 uniformed personnel of the Pakistan Armed Forces, including some Bengali soldiers who had remained loyal to Pakistan. The remaining 10,324 to 12,500 prisoners were civilians, either family members of the military personnel or collaborators (Razakars).
It is estimated that members of the Pakistani military, supporting pro-Pakistani Islamist militias and the Razakars killed between 300,000 and 3,000,000 civilians in Bangladesh. As a result of the conflict, a further eight to ten million people fled the country to seek refuge in India.
During the war, members of the Pakistani military and the Razakars raped between 200,000 and 400,000 Bangladeshi women and girls in a systematic campaign of genocidal rape.
The Indo-Pakistani conflict was sparked by the Bangladesh Liberation War, which was a result of the violation of the rights of East Pakistan by the Pakistan Army. The political tensions in East Pakistan had its origin in the creation of Pakistan as a result of the partition of India by the United Kingdom in 1947; the popular language movement in 1950; mass riots in East Bengal in 1964; and the mass protests in 1969. These led to the resignation of President Ayub Khan, who invited army chief General Yahya Khan to take over the central government. The geographical distance between the eastern and western wings of Pakistan was vast; East Pakistan lay over 1,600 kilometres (1,000 mi) away, which greatly hampered any attempt to integrate the Bengali and the Pakistani cultures.
To overcome the Bengali domination and prevent formation of the central government in Islamabad, the controversial One Unit programme established the two wings of East and West Pakistan. West Pakistanis' opposition to these efforts made it difficult to effectively govern both wings. In 1969, President Yahya Khan announced the first general elections and disestablished the status of West Pakistan as a single province in 1970, in order to restore it to its original heterogeneous status comprising four provinces, as defined at the time of establishment of Pakistan in 1947. In addition, there were religious and racial tensions between Bengalis and the multi-ethnic West Pakistanis, as Bengalis looked different from the dominant West Pakistanis.
The East Pakistan's Awami League leader Sheikh Mujibur Rahman stressed his political position by presenting his Six Points and endorsing the Bengalis' right to govern themselves. The 1970 Pakistani general election, resulted in Awami League gaining 167 out of 169 seats for the East Pakistan Legislative Assembly, and a near-absolute majority in the 313-seat National Assembly, while the vote in West Pakistan was mostly won by the socialist Pakistan Peoples Party. The League's election success caused many West Pakistanis to fear that it would allow the Bengalis to draft the constitution based on the Six Points and liberalism.
To resolve the crisis, the Admiral Ahsan Mission was formed to provide recommendations. Its findings were met with favourable reviews from the political leaders of West Pakistan, with the exception of Zulfikar Ali Bhutto, the chairman of the Pakistan Peoples Party.
However, the military leadership vetoed the mission's proposal. Zulfikar Ali Bhutto endorsed the veto, and subsequently refused to yield the premiership of Pakistan to Sheikh Mujibur Rahman. The Awami League called for general strikes throughout the country. President Yahya Khan postponed the inauguration of the National Assembly, causing disillusionment among the Awami League and their supporters throughout East Pakistan. In reaction, Sheikh Mujibur Rahman called for general strikes that eventually shut down the government, and dissidents in the east began targeting the ethnic Bihari community, which largely supported West Pakistan.
In early March 1971, approximately 300 Biharis were slaughtered in riots by Bengali mobs in Chittagong alone. The government of Pakistan used the "Bihari massacre" to justify its deployment of the military in East Pakistan on 25 March, when it initiated its military crackdown. President Yahya Khan called on the military—which was overwhelmingly led by West Pakistanis—to suppress dissent in the east, after accepting the resignation of Lieutenant-General Yaqub Ali Khan, the chief of staff of the East Pakistani military.
Mass arrests of dissidents began and, after several days of strikes and non-cooperation, the Pakistani military, led by Lieutenant-General Tikka Khan, cracked down on Dhaka on the night of 25 March 1971. The government outlawed the Awami League, which forced many of its members and sympathisers to seek refuge in Eastern India. Mujib was arrested that night at about 1:30 am (as per Radio Pakistan's news on 29 March) and taken to West Pakistan. Operation Searchlight, followed by Operation Barisal, which attempted to kill the intellectual elite of the east.
On 26 March 1971, Major Ziaur Rahman of the Pakistan Army declared the independence of Bangladesh on behalf of Sheikh Mujibur Rahman.
In April, the exiled Awami League leaders formed a government-in-exile in Baidyanathtala of Meherpur. The East Pakistan Rifles and Bengali officers in Pakistan's army, navy, and marines defected to the rebellion after taking refuge in different parts of India. The Bangladesh Force, namely the Mukti Bahini, consisting of a conventional force and a guerilla force, was formed under the retired colonel Mohammad Ataul Gani Osmani.
There was also a meeting between Prime Minister Indira Gandhi and President Richard Nixon in November 1971, in which the former rejected American advice against intervening in the conflict.
India's involvement in the Bangladesh Liberation War
After the resignations of Admiral S.M. Ahsan and Lieutenant-General Yaqub Ali Khan, the press began airing reports of the Pakistani military's widespread genocide against their Bengali citizens, particularly targeting the minority Bengali Hindus, which led to approximately 10 million people seeking refuge in the neighbouring states of Eastern India. The Government of India opened the East Pakistan–India border to allow Bengali refugees to find shelter; the governments of West Bengal, Bihar, Assam, Meghalaya and Tripura established refugee camps along the border. The resulting flood of impoverished East Pakistani refugees strained India's already overburdened economy.
The Indian Government repeatedly appealed to the international community for assistance, but failed to elicit any response, despite External Affairs Minister Swaran Singh meeting foreign ministers of other countries. Prime Minister Indira Gandhi on 27 March 1971 concluded that, instead of taking in millions of refugees, it was better to go to war with Pakistan, and expressed the full support of her government for the independence struggle of the people of East Pakistan. On 28 April 1971, the Union cabinet ordered the Chief of the Army Staff General Sam Manekshaw to "Go into East Pakistan". East Pakistan military officer defectors and elements of the Indian Research and Analysis Wing (RAW) immediately started using the Indian refugee camps for the recruitment and training of Mukti Bahini guerrillas.