|C. Coimbra photo|
The prize-winner, Rajendra Singh, is dubbed "the Water Man of India".
The judges say his technique is cheap, simple, and that his ideas should be followed worldwide.
Mr Singh uses a modern version of the ancient Indian technique of rainwater harvesting.
It involves building low-level banks of earth to hold back the flow of water in the wet season and allow water to seep into the ground for future use.
--From BBC News