Why the west flowing rivers of peninsular India don’t form deltas?

The slope of the Western Ghats is steep and that is the reason that these rivers have a rapid flow. They don’t have to travel much distance to drain into the sea. As a result, they don’t carry much sediments required to form deltas. At the same time, the Narmada and Tapti rivers flow in the rift valleys. So the eroded material carried by them gets deposited in the fractures of the fault zones.

Further Reading:

• West Flowing Rivers of Peninsular India
• The Major Indian River Systems