On June 19, 2013, NASA’s Terra and Aqua satellites captured striking images of smoke billowing from illegal wildfires on the Indonesian island of Sumatra.
The smoke blew east toward southern Malaysia and Singapore, and news media reported that thick clouds of haze had descended on Singapore, pushing pollution to record levels.
Singapore’s primary measure of pollution, the Pollutant Standards Index—similar to the Air Quality Index used by the U.S. Environmental Protection Agency—rose to 371 on June 20, 2013, the highest level ever recorded. The previous record occurred in 1997, when the index hit 226. Health experts consider any level above 300 to be “hazardous” to human health. Levels above 200 are considered “very unhealthy.”
Image courtesy of NASA.