Fires set as part of the slash-and-burn agriculture and clearing of land in Indonesia have occurred since the 1960s, choking not only parts of the country but also neighbouring Singapore and Malaysia. The frequency and intensity of burning have, unfortunately, increased in recent years. In some bad episodes that occurred in 1997, 2013 and 2015, the affected countries' respective air pollution index readings for some areas went far beyond levels hazardous to human health.
Forest fires bring about not only huge devastation of the ecosystem, but also harm public health. Millions of people are kept indoors when air pollution rises to hazardous levels, and tens of thousands in search of treatment for respiratory, eye and skin ailments overwhelm medical clinics and hospitals. The haze also disturbs air and sea transportation in affected countries. Overall, haze pollution generated from such forest fires exacts a heavy economic toll on society.