The process of partition had been started in 1940 when Muslim League Propounded Two Nation Theory.
This process involved various problems:
1. Areas were supposed to be distributed on the basis of religions majority i.e. Muslim majority areas built Pakistani territory and rest stayed with India. It created communal riots in country.
2. No single belt of muslim majority was the part of British India. They were concentrated in East and West. Hence, it was decided that Pakistan will comprise two territories namely East and West Pakistan separated by long expansion of India territory.
3. All muslim majority areas did not want to be merged with Pakistan i. e. it was opposed in NWFP. But ultimately NW.FP was made to merge with Pakistan.
4. Another problem belonged to minorities on both sides of border i. e. Lakhs of Hindus and Muslims and Sikhs from both the sides were left with no option except to leave their homes.