Question

why did Northern Plains are densely populated area

Answer 1

There is very fertile soil appropriate for agriculture so they are densly populated.So there human life is easy

Answer 2

Answer:

Answer: For the following reasons, India's northern plains are densely populated: They consist of a "large plain of alluvial soil" and alluvium deposition over millions of years in a vast basin placed on the "foothills of the Himalayas", it will be make this plain will be more fertile.

I hope this will help you