Originally posted by: nautankitadka
India’s then Governor-General and Viceroy Lord Mountbatten addressed the nation over All India Radio on June 3, 1947. He announced his 3rd June Plan, according to which India would be given independence on August 15, 1947. Under this Plan, the British would transfer power to two successor authorities — the Congress and the Muslim League. As per the plan, a Boundary Commission (eventually headed by Sir Cyril Radcliffe, a London barrister who had never previously visited India), was formed as suggested by Lord Listowel, Secretary of State for India, which was tasked to delineate the precise boundaries between India and Pakistan in the provinces of Bengal and Punjab. Radcliffe had worked with Mountbatten earlier and since he had never been to British India, he was considered unbiased. Both Nehru and Jinnah agreed to the appointment, which was formally approved by the Partition Council. At the time of his appointment, Radcliffe was Vice-President of the London Bar Association.
According to this 3rd June Mountbatten Plan, a referendum would be held in the NWFP (as Nehru had agreed earlier), and another in the Muslim-majority Sylhet district of Assam (the rest of which would remain in India). Remarkably, no referendum was called for the Chittagong Hill Tracts, where non-Muslims (Buddhists, Hindus and Christians) were in a strong majority or for the cities of Karachi or Hyderabad, Sindh, (with clear non-Muslim majorities) as they would almost certainly have voted to remain within India.
Source: https://www.tribuneindia.com/news/archive/comment/remembering-mountbatten-s-june-3-plan-599572