It's Background History!!

Bangladesh....
      Formerly called East Pakistan has remained in a state of political instability ever since the turmoil of civil war.Portuguese traders were the first one and missionaries were the first Europeans to reach Bengal in the latter part of the 15th century. They were followed by representatives of the Dutch, French, and British East India Companies. By the end of the 17th century, the British presence on the Indian subcontinent was centered in Calcutta.
      During the 18th and 19th centuries, the British extended their commercial contacts and administrative control beyond Calcutta to Bengal. In 1859, the British Crown replaced the East India Company,extending British dominion from Bengal, which became a region of India, in the east to the Indus River's in the west.....The rise of nationalism throughout British-controlled India in the late 19th century resulted in animosity between the Hindu and Muslim communities. In, 1885 the All-India National Congress was founded with Indian and  British membership.The subsequent history of the nationalist movement was characterized by periods of Hindu-Muslim cooperation, as well as by communal antagonism.
       When British India was partitioned and the independent dominions of India and Pakistan were created in 1947, the region of Bengal was divided along religious lines. The Muslim eastern half was designated East Pakistan- and made part of the newly independent Pakistan-while the Hindu western part became the Indian state of West Bengal. In the other hand, East Pakistanis felt exploited by the West Pakistan-dominated central  government. Linguistic, cultural, and ethnic differences also contributed to the estrangement (hostile;indifferent) of Eastern West Pakistan. Bengalis strongly resisted attempts to impose Urdu as the sole official language of Pakistan.Responding to this distress, Sheikh Mujibur Rahman in 1948 formed a students' organization called "Chhatra League". In 1949, Maulana Abdul Hamid Khan Bhasani and some other Bengali leaders formed the East Pakistan "Awami Muslim League"(AL), a party designed mainly to promote Bengali interests. This party dropped the word Muslim from its name in 1955 and came to be unknown as Awami League. Mujib became president of the AL in 1966 and emerged as leader of the Bengali autonomy movement. In 1966, he was arrested for his political activities.
       On March 26, 1971, Bengali nationalists declared an independent "People's Republic of Bangladesh. As fighting grew between the army and the Bengali "mukti bahini or "freedom fighters", an estimated 10 million Bengalis, mainly Hindus, sought refuge in the Indian states of Assam and West Bengal. On April 17, 1971, a provisional government was formed in Meherpur, district in western Bangladesh bordering India with Sheikh Mujibur Rahman, who was in prison in Pakistan, as President, Syed Nazrul Islam as Acting President, and Tajuddin Ahmed as Prime Minister.
       The crisis in East Pakistan produced new strains in Pakistan's troubled relations with India.The two nations had fought in 1965, but the refugee pressure in India in the fall of 1971 produced NEW tensions in the east.On December 1971, Pakistani forces SURRENDERED, and Bangladesh (meaning "Bengal Country) was BORN. The new country became a parliamentary democracy under a 1972 constitution.The first government of the new station of Bangladesh was formed in Dhaka with justice Abu Sayeed Choudhury as President, and Sheikh ujibur Rahman("Mujib")- who was released from Pakistani prison in early 1972>>as Prime Minister.


http://www.state.gov/p/sca/ci/bg/
http://www.wateraid.org/uk/what_we_do/where_we_work/bangladesh/390.asp
https://www.cia.gov/library/publications/the-world-factbook/geos/bg.html