Explain how Northern Plain was formed.

Tectonic setup (foreland basin forms):
When the Indian Plate collided with the Eurasian Plate (Cenozoic era), the Himalayas rose. In front of this rising mountain belt, the crust downwarped to create a long, shallow trough called a foreland basin/foredeep stretching from the Indus in the west to the Brahmaputra in the east.

Huge sediment supply from young mountains:
The new, high Himalayas weathered rapidly. Himalayan rivers—the Indus, Ganga and Brahmaputra and their tributaries—eroded rock and carried alluvium (boulders, pebbles, sand, silt, clay) into this trough.

Progressive infilling over millions of years:
Layer upon layer of river-borne alluvial deposits gradually filled the foreland basin, converting it into a vast, flat alluvial plain. In some places, the alluvium is hundreds to thousands of metres thick.

River action shaped the surface:
As the rivers spread and shifted courses (meandering, flooding, avulsions), they built natural levees, floodplains, point bars and ox-bow lakes, giving the plain its smooth relief and fertile soils.

Regional belts within the plain (north → south/east):

• Bhabar: A narrow belt along the Himalayan foothills where fast streams drop coarse pebbles and boulders; soils are very porous.
• Terai: Just south of Bhabar; waterlogged, marshy zone where streams re-emerge.
• Bhangar:Older alluvium (slightly elevated terraces), often with kankar (calcareous concretions).
• Khadar:Newer alluvium in the active floodplains; very fertile and renewed by annual floods.
• Deltaic plain (east): Where the Ganga–Brahmaputra system spreads into distributaries and deposits fine silt, forming the world’s largest delta (including the Sundarbans).

Sub-regions along its length:

• Western (Indus) Plain – Punjab–Haryana–Rajasthan sector.
• Middle (Ganga) Plain – Uttar Pradesh–Bihar.
• Eastern (Brahmaputra) Plain – Assam valley and the Ganga–Brahmaputra delta (West Bengal–Bangladesh).

The Northern Plain of India is a vast alluvial plain formed by the deposition of sediments brought down by the Indus, Ganga and Brahmaputra river systems into a downwarped foreland basin created during the uplift of the Himalayas.

Why it matters

• Extremely fertile soils (newer khadar) → intensive farming (wheat, rice, sugarcane, jute).
• Gentle relief + navigable stretches → dense transport networks and high population density.
• Flood control & river training needed due to active rivers and annual monsoon floods..