What is your theory of the situation in China and India?

In 2008, India's estimated population was approximately 1,206,735,000, while China's was around 1,328,020,000. India ranked as the second most populous country, while China remained the most populous

Based on this data, do you think the crossed population stayed in those territories longer due to the possible number of available victims, or did they migrate north?

English is not my first language!