Light as air

A crowd releases lanterns into the air as they celebrate the Yee Peng festival, also known as the festival of lights, in Chiang Mai in northern Thailand on Friday. The lanterns used during the festival — celebrated on the full moon of the 12th lunar month every year — are made from a thin fabric such as rice paper stretched over a frame to which a candle or fuel cell is attached. When the fuel cell is lit, the resulting hot air trapped inside the lantern creates enough lift for it to float into the sky. Because they are a hazard to passing aircraft, the lanterns are increasingly subject to government restrictions. In Chiang Mai, authorities cancelled 78 flights in and out of Chiang Mai Airport on Friday and yesterday, and rescheduled 79 more flights.