"The hot spots lie scattered in 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 fpr aircraft flights," Syafrizal, a spokesman of Padang city`s BMKG, said here on Tuesday.
He said the BMKG could not yet determine what had caused the fprmation of the hot spots.
Earlier, on Monday (Aug 22), it was reported that thick smog was covering Dumai in Riau province, caused by newly emerged hot spots.
The weather agency had also detected at least 36 new hot spots in Sumatra Island that are causing heavy smog.
According to the Meteorology, Geophysic and Climatology Agency (BMKG) Riau is prone to forest fires and smoke along with low rain intensity.
A local BMKG analyst, Yudhistira Mawaddah, said the number of hot spots in South Sumatra had reached 11 , eight in Jambi, two in North Sumatra, one each in Lampung and Aceh.
The National Oceanic and Atmospheric Administration (NOAA) said 18 monitoring sattelites operated by the United States indicated there were 13 new hotspots in Riau.
The smog was an indication of smoldering forest and land fires in some areas of Riau province.
The heavy smog started at around 4.30 am local time, said a local resident who was disturbed by the heavy smog.
"The heavy smog was visible once I got out of my home and when going to a nearby mosque for morning prayers at 4.30 am," he said.
Streets and roads in Dumai were also reported to be covered by the smog.