Cochin International Airport in southern India's Kerala state may be best known as the gateway to the tourist beaches and houseboats of the region's famous backwaters. Now it has a new claim to fame: The world's first solar airport. Since August, the airport has used 46,000 solar panels laid across 45 acres to power all its electricity needs, and sell excess power to the government-run grid. At night, when the sun doesn't shine, it pulls some of that power back from the grid, making the airport effectively carbon neutral." Over the next 25 years, the project is expected to reduce carbon emissions by the equivalent of planting 3 million trees. The move to solar power is also expected to help cut pollution in Kochi, an industrial city ranked the 24th most polluted in India. Based on the results at Kochi, India's government has directed 125 airports run by the Airport Authority of India to generate at least 1 megawatt of solar power each by March 2016. If a medium-sized airport such as Kochi, with just 1,300 acres of land, can produce sufficient electrical power for its operations, larger airports such as Delhi, with 5,000 acres, and Bangalore, with 3,000 acres, should be able to meet some of their power demand too, said Kurian, the Kochi airport's managing director. "We are expecting not only other Indian airports, but airports in other countries, also to follow suit," he said. "Every day we are being asked for expert advice and are answering queries from across the world."