Population distribution maps, such as this one show North Eastern India (right below Nepal) as being the most densely populated region.
A video I just watched on human population through time shows that region of India always being the most populated. I'm convince that this area was the center of Indian civilization through time. What factors have contributed to this? And why don't we see similar growth in other parts of India through time?
Take a look at the topographical map of India. People tend to cluster around river plains. Most of the major civilizations of the pre-modern world (actually, even modern world) are centered around river plains. India is no exception.
