What are the reasons for this? Is it simply because fertile lands of Indian Subcontinent were able to sustain more population? What is the contribution of events such as Black death, mongol invasion, world wars and immigration to new world on it? Are there any other factors?
Here is the link from the FAQ:
If you are interested in this subject, you should definitely read Jared Diamond's "Collapse"
He gives a very detailed, scientific approach to how certain areas are able to maintain large populations while others may stay low consistently while other boom and bust over time.
Edit:Really? Downvoted because I gave a reading suggestion about a topic this person was asking about? And oh by the way, the book literally answers this guy's question.