It began nearly a year ago when they introduced solar panels at the Rajiv Gandhi Medical College. The system could heat 19,050 litres of water everyday and the electricity bill dropped by a remarkable Rs 9 lakh. Buoyed by the success, the technology was soon adopted in other hospitals run by the corporation. "We showed that solar water heating can be commercially viable through this project," says Thane municipal commissioner Sanjay Sethi, the prime motivator behind the conservation drive.