Padang – The Meteorology, Climatology and Geophysics Agency (BMKG) detected 203 hot spots across Sumatra on Tuesday, an official said.

"The hot spots are scattered across several provinces, namely: South Sumatra, Jambi, Bengkulu, Lampung and Riau. Thick haze is covering Sumatra island at the moment; fortunately visibility is still at least 10 kilometers, which means it's still safe for aircraft flights," Syafrizal, a spokesman from BMKG's Padang office, said as quoted by Antara news agency on Tuesday.

He said the BMKG could not yet determine what had caused the formation of the hot spots. On Monday, thick haze blanketed Dumai in Riau. According to the BMKG, Riau is prone to forest fires, which then cause haze amid low rain intensity.