Air pollution in major Southeast Asian and Chinese cities ranks among the worst in the world and contributes to the deaths of about 500,000 people each year, said Michal Krzyzanowski, an air quality specialist at the WHO’s European Center for Environment and Health in Bonn, Germany. Drifting smoke from purposely set forest fires in Indonesia caused Malaysia to declare a state of emergency last week in two areas outside Kuala Lumpur. Parts of Thailand were also blanketed in the haze. Malaysian health officials said hospitals reported a 150 percent increase in breathing problems and seven people who had a history of respiratory problems reportedly died.