The Partition of India was the historical division of the countries of India and Pakistan. It started with Pakistan's independence from India on 17 August 1947 and resulted in mass displacement and deaths.
There was often religious tension between the peoples of both countries as India was mainly Hindu whereas Pakistan was intended to be a nation for Muslims. Hindu and Muslim intermarriages, such as with Prem and Umbreen, were shunned. Prem was killed by his own brother Manish for this, who had previously killed the holy man who was to perform his wedding.
The Thirteenth Doctor, Yasmin Khan, Ryan Sinclair and Graham O'Brien visited India and Pakistan during the partition. (TV: Demons of the Punjab)