In 1971, India won the war against Pakistan that resulted in the birth of Bangladesh (then East Pakistan).
Pakistan lost half its country, its forces in the East, and had to publicly surrender to India. It was also the largest military surrender after World War II.
So what happened during 1970s an internal crisis occured in Pakistan. So what happwned is when the 1st general elections took place a split occured between West Pakistan and East Pakistan. In West Pakistan , Zulfikar Ali Bhutto won the elections and in East Pakistan, the Awami league leaded by Sheikh Mujibur Rehman won . Now the bengali population that was in east Pakistan, they voted for Awami league because they were protesting against the dominance of West Pakistan and they were being treated as 3rd class citizens. But the Pakistan rulers in West and East Pakistan were not ready to accept this demovratic verdict.In 1971, Pakistani Army began to commit the genocide on innocent Bengali population, particularly in East Pakistan. So former Prime Minister Indira Gandhi decided to take action against Pakistan at the same time by give refuge to civilians from other side of the border. Throughout 1971, India had to bear the burden of some 80 lakh refugees who fled from East Pakistan and took shelter in India. After months of diplomatic tension and military build up a full scale war broke out between India and Pakistan on dec 1971. The war lasted 13 days and was one of shortest wars in history. The war ended after the Chief of Pakistani forces general AAK Niazi along with his troopes surrendered to Indian Army and Bangladesh’s Mukti Bahini.
General AAK Niazi signed the instrument of surrender in Dhaka marking the formation of East Pakistan as new nation of Bangladesh. Pakistan also lost half its territory after formation of Bangladesh. On august 1972 India signed Shimla agreement with Pakistan under which the former agreed to release all the 93,000 Pakistani prisoners of war.
