Question

what are the factors responsible for making the northern plains a very productive part of India class 9

Answer 1

This is because the climatic conditions are good at the northern plains. I think it can help you.

Answer 2

The Northern Plain was developed by the sediments brought in by the three significant rivers and their tributaries i.e River Indus, Ganga, and the Brahmaputra.  These rivers have deposited Alluvium at the foothills of the Mountains for millions of years.  Alluvium is typically formed up of the various material like a fine particle, sand , mud and extensive part of silt and pebbles which is highly fertile. These sediments who are bween collected for the millions of year are now turned into the productive land of Northern Plains.