Explanation:

The tank irrigation is practised mainly  in  the  peninsular  India due to the following reasons

1. The undulating relief and hard rocks makes it difficult to dig  canals and wells.
2. There is little percolation of rain water due to hard rock structure and ground water is not available in large quantity.
3. Most of the rivers of this region are seasonal and dry up in summer season. Therefore, they cannot supply water to canals throughout the year.
4. The scattered nature of population and agricultural fields also favours tank irrigation.