Partition of India

The main problems of population migration that arose from the independence of the Indian sub-continent from the British Rule was not the creation of India and Pakistan as such. Jinnah wanted partition of the country into Pakistan and India, mainly on religious grounds, but he also argued fiercely with Mountbatten and his advisers (I read in one of Mountbatten's biographies that the argument at the final stages of independence went through a whole night), against partition of the provinces of Bengal and Punjab and demanded that these two Muslim majority provinces which had existed for many years with their democratic provincial legislatures and governments must remain in tact and be allocated to Pakistan. Mountbatten was adamant that if religion was the basis to divide the country as a whole then the same principle must be applied to these provinces as well.
If these provinces were not partitioned but in their wholeness of existence as before became part of Pakistan, then India would have remained a Hindu country with large Muslim minority, and Pakistan a Muslim country with large Hindu ( or Sikh and other) minorities. Both countries therefore would have been forced to pursue only secular democratic policies acceptable to all factions of populations within them, ( like the erstwhile British), whether it was largely a Hindu or a Muslim country.
In such an event independence and partition would have provided a much better opportunity for peaceful coexistence between the two countries with political thinking very much like the British, with much higher potential for development and progress for both India and Pakistan.
But of course Mountbatten was no Solomon!