Q1.
Look at the physical map of India given at the end of the book. Notice the direction of the flow of the rivers.
Answer
Follow each blue line from its source to the sea and a clear pattern appears. India's rivers fall into three groups:
| Group | Rivers | Direction and outlet |
|---|---|---|
| Himalayan rivers | Ganga, Yamuna, Brahmaputra | Flow south, then east across the plains into the Bay of Bengal |
| Indus and its tributaries | Flow west/south-west into the Arabian Sea | |
| East-flowing peninsular rivers | Mahanadi, Godavari, Krishna, Kaveri | Rise near the Western Ghats and cross the whole plateau west to east into the Bay of Bengal, building deltas |
| West-flowing peninsular rivers | Narmada, Tapti | Flow east to west into the Arabian Sea, forming estuaries, not deltas |
Why most peninsular rivers flow east: the plateau is tilted — high along the Western Ghats, sloping gently down towards the east. Water always runs downhill, so it crosses the plateau to the Bay of Bengal. The Narmada and Tapti are exceptions because they flow west along rift valleys (long trough-shaped cracks in the land).
Check it yourself: a river that flows a long way over gentle land drops its sediment slowly and builds a delta; a short, fast river reaching the sea quickly forms an estuary. That is exactly why the east coast has deltas and the west coast has estuaries.