Natrani is an amphitheatre that belongs to danseuse Mallika Sarabhai and her Darpana Academy. It opened recently on the Ahmedabad Riverfront. One of its most interesting features is the rainwater harvesting system underneath the stage. It is an open-air theatre, so air conditioning is not possible. Panasia Engineers Pvt Ltd. designed a natural cooling system using the water fl owing under every tier, to cool down the structure.

A large tank under the stage stores the water from the rainwater collection system. A pump sends it to a higher level, where it is cooled by a natural process. The cooled water then comes down by gravity through the pipes under the tiers and empties into the tank. The water absorbs the solar heat from the entire structure, thus keeping it cool and comfortable. 

Additional comfort is provided by the displacement ventilation system that provides a gentle flow of cool filtered air from several small outlets distributed along the tiers. They form a blanket of cool air over the stadium by displacing the warm stale air.