Question

how were northern plains of india formed

Answer 1

About 55 million years ago, the Indian tectonic plate crashed into the Eurasian plate. This resulted in the formation of the Himalayan mountains as the underwater rocks of that time were lifted up by the force of the crash of the two plates. Rivers began to flow from the Himalayas which deposited sediment in the foothills of the mountain. Over time, as more and more sediment was deposited, it became the vast plains that we know today as the Northern Plains of India.