Gangetic Plains

The Shiwaliks end rather abruptly in the great northern plains that constitute a flat mass, with Delhi being situated on the highest point.
The plains extend to the Bay of Bengal (the lowest point) in the east. By this point, land elevation starting from Delhi drops by about 200m.

The plains are so fertile that in some places the layer of rich alluvium soil measures more than 5,000m! They also contain some of the largest reserves of underground water in the world.
Along with the Yamuna, the Ganga drains a large part of the plains and carries an estimated million tonnes of silt each year.