With urban India growing by leaps and bounds, it is expected to experience a severe water crisis by 2020 and the per capita availability of water is projected to be less than 1,000 cubic metres.
By the year 2020, says a World Bank report, most major Indian cities will run dry. India's supply of water too is rapidly dwindling primarily due to mismanagement of water resources, although over-pumping and pollution are also significant contributors.
Rainwater harvesting is one of the most promising alternatives for supplying water in the face of increasing water scarcity and escalating demand. Water from the roof is collected and stored in underground tanks after proper filtration to remove the collected contaminants. The water collected can be used to recharge aquifers or stored for usage as utility water.