Question

Inland waterways are more in Northern India than southern India why

Answer 1

Because North has more trade scope than South.....
We don't have much rivers on South

Answer 2

In northern India rivers are mostly nourished by glacier water, which helps in maintaining the river water round the year. Hence it is easier to make the waterways in northern India.  

In southern India most of the rivers are originated from peninsula and they are perennial type hence waterways do not get water for year around mostly.  This is the reason Inland waterways are more in Northern India than southern India.