Some 6,500,000 Muslims migrated to Pakistan from India at the time of independence in 1947, WORLD’S BIGGEST MIGRATION OF HUMAN BEING ON EARTH

When the British Indian Empire was partitioned in 1947, 4.7 million Sikhs and Hindus left
what is today Pakistan for India, and 6.5 million Muslims migrated from India to Pakistan.
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Thus, over just a few months, the population of Pakistan increased by 1.8 million people, or
6 per cent. However, this increase was mostly in the urban areas of the Sindh and Punjab
provinces.