The haze is an annual problem in Indonesia caused by fires set in forest and on carbon-rich peatland in Indonesia to clear land for palm oil and pulpwood plantations.
The blazes occur mainly on Indonesia's Sumatra island and the Indonesian part of Borneo, with monsoon winds typically blowing the haze over nearby Singapore and Malaysia.
There are currently about 180 hotspots in Indonesia over about six provinces, but the number is significantly lower than in 2015 when haze cloaked large parts of the region causing huge numbers to fall ill and sending diplomatic tensions soaring.
Last year, researchers from Harvard and Columbia universities in the United States estimated that the 2015 smog outbreak may have caused over 100,000 premature deaths.