2015 Southeast Asian haze

The 2015 Southeast Asian haze was an air pollution crisis affecting several countries in Southeast Asia, including Brunei, Indonesia (especially its islands of Sumatra and Borneo), Malaysia, Singapore, southern Thailand, Vietnam, Cambodia and the Philippines. The haze affected Indonesia from at least late June, to the end of October, turning into an international problem for other countries in September.

Source: Wikipedia — 2015 Southeast Asian haze (CC BY-SA 4.0)