The scenario describes the migration resulting from the partition of India in 1947, which led to the displacement of approximately 17 million individuals due to the division of the country along religious lines. This significant political change resulted in communal violence and the forced movement of people to ensure that communities were aligned with the newly formed states of India and Pakistan.
Given this context, the most appropriate response is:
forced political migration
This is because the migration was primarily driven by political changes and conflicts associated with the partition, rather than economic or environmental factors.