Smoky haze clings to villages in northern Thailand during the dry season between January and April, when the monsoon rain stops and garbage burning begins. People here burn everything that needs disposing, from plastic bags to rice straw left over from harvest. Burning is the cheapest and fastest way to remove trash in the largely rural region without infrastructure and to prepare fields for planting when the rains return. Most people in the region are subsistence rice farmers who have been burning their trash and fields for at least 100 years. A short drive from the burn zone Phongtape Wiwatanadate, M.D., Ph.D., director of Community Medicine at Chiang Mai University, studies the health effects of burning, namely asthma and lung cancer. Thailand’s northern province, where burning is rampant, has one of the highest rates of lung cancer in the developing world, with 500 to 600 new cases appearing every year in a population of 1.7 million people, comparable to the incidence of lung cancer in other rapidly developing countries in Southeast Asia, according to the most recent 2008 data from the World Health Organization.1 Lung disease in northern Thailand has been linked to airborne carcinogens, including