Why the majority of peninsular rivers fall into Bay of Bengal ........

Geography India - Water bodies

Why the majority of peninsular rivers fall into Bay of Bengal?

Submergence of western part of Peninsular in Arabian sea during the early Tertiary period.

Presence of Satpura in the northern part of Peninsular block.

Presence of igneous rocks.

Collision of Indian plate with the Eurasian plate created a trough faulting in the Peninsular block

Slight tilting of the Peninsular block from northwest to the southeastern direction gave orientation to the entire drainage system towards the Bay of Bengal during the early Tertiary period.
The tilting was caused when Western part of Peninsula cracked and submerged in the Arabian sea that thereby disturbed the river's course during the early Tertiary period. It has disturbed the symmetrical plan of the river on either side of the original watershed.