Self-determination
In 1947, India gained independence from the British Empire. The empire was in decline but adapted to these circumstances by creating the British Commonwealth—since 1949 the Commonwealth of Nations—which is a free association of equal states. As India obtained its independence, multiple ethnic conflicts emerged in relation to the formation of a statehood during the Partition of India which resulted in Islamic Pakistan and Secular India. Before the advent of the British, no empire based in mainland India had controlled any part of what now makes up the country's Northeast, part of the reason for the ongoing insurgency in Northeast India. In 1971 Bangladesh obtained independence from Pakistan.
Treaty of Peace Between Japan and India
The British Empire, of which India was a part, had full diplomatic relations with Japan became involved in World War II. After the war Japan was under U.S. occupation and India gained its independence on August 15, 1947. In 1951, the San Francisco Peace Conference was held with Indian Prime Minister Jawaharlal Nehru refusing to attend the conference, because he considered the provisions of the San Francisco Treaty to be limiting Japanese sovereignty. After the conference, on April 28, 1952, Japan regained their sovereignty with the withdrawal of most occupational forces.