Explain how Northern Plain was formed.

Hint: The northern plains are considered to be the largest alluvial tract of the world, extending from east to west for about 3,200 km approximately and are the youngest physiographic feature in India.

Complete Step by Step Answer:
The Northern Plains of India have been formed by the Ganga, the Indus and the Brahmaputra rivers and their tributaries. The northern part of the Indian Peninsula subsided due to the upliftment of the Himalayas in the Tethys sea and resulted in a large basin. This basin accumulated sediments from the rivers which came from the mountains in the north and from the peninsula in the south. With the help of these extensive alluvial deposits, the northern plain was formed. The northern plains have supported the rise of early civilizations. Both the Indus and Ganga civilizations evolved in the plains as the plains provided them agriculture with rich soil cover, suitable climate and adequate water resources.

It is said that the northern plain is an area of monotonous relief having little variety in its geomorphological features and extending for 3,200 km between the Indus and the Ganga, all along the foot of the mountain rim. Its width varies from 150 to 300 km. The longitudinal extent from the banks of the rivers Ravi and Sutlej to the Ganges delta is 2,400 km. The plains are narrowest in Assam, 90 to 100 km and broaden towards the west. They are 160 km wide near the Rajmahal Hills and 280 km near Allahabad, the confluence of the Ganga and the Yamuna.

Note: The northern plains are classified into three major divisions - the Bhabar, the Tarai and the Alluvial plains. The alluvial plains are further divided into two sections the Bhangar and the Khadar plains.