Write a note on rooftop rain water harvesting in India.

(l) Rooftop rainwater harvesting is the most common practice in Shillong, Meghalaya. Nearly every household in the city has a rooftop rainwater harvesting structure. Around 15-25 per cent of the total water requirement of the household comes from rooftop water harvesting.
(ii) Rooftop harvesting was common across the towns and villages of the Thar. The rainwater that falls on the sloping roofs of houses is taken through a pipe into an underground Tanka built in the main house or in the courtyard. However, sadly the practice of rooftop rainwater harvesting is on the decline as plenty of water is available due to the perennial Rajasthan Canal.