Question

Island waterways are more in north India then south India. Why?

Answer 1

The rivers in Southern India are non perennial. The rivers in the North like Ganga and Brahmaputra are perennial rivers.

The rivers in the South has formed harmful steep waterfalls...thus the importance of inland waterways is declining there.

Diversion of river water for irrigation is one of the main reasons for decline of importance of inland waterways in South India. There is insufficient depth of water.