The two major west flowing rivers are the Narmada and the Tapi. This exceptional behavior is because these rivers didn't form valleys and instead they flow through faults (linear rift, rift valley, trough) created due to the bending of the northern peninsula during the formation process of Himalayas.

Where do Narmada and Tapi flow into?

India and flows westwards over a length of 1,312 km (815.2 mi) before draining through the Gulf of Khambhat into the Arabian Sea, 30 km (18.6 mi) west of Bharuch city of Gujarat.

Why rivers flow from west to east in India?

Answer: major peninsular rivers flow from west to east due to the gradient of land but narmada and tapi flows in the opposite direction because they do not flow on the plateau surface but in rift valleys and these valleys happen to have an opposite gradient.