What political event caused the political boundaries to change in south asia?

The Partition of British India in 1947 is a significant political event that caused the political boundaries to change in South Asia. Endorsed by the Indian Independence Act of 1947, it resulted in the creation of two separate nations, India and Pakistan. The partition was primarily based along religious lines, with predominantly Hindu areas becoming part of India, while areas with a Muslim majority formed the new state of Pakistan. This partition had a considerable impact on the political map of the region, leading to the drawing of new borders and subsequent migration and displacement of people, resulting in widespread violence and communal tensions.