JAKARTA - The haze that affected Singapore over the weekend was from forest fires burning in Rokan Hilir regency in Riau province, said Indonesia's National Disaster Management Agency (BNPB) on Monday (Aug 29).
Dr Sutopo Purwo Nugroho, who heads of the Data and Information Division at BNPB, said winds caused by the movement of a tropical cyclone in the Philippines had carried the thick smoke to Singapore.
"The cyclone not only sucked in the haze but also the moisture in Riau, making (the air) dryer," he told reporters at a media briefing at the BNPB headquarters in Jakarta.
Dr Sutopo, who is also the agency's spokesman, was referring to Typhoon Lionrock, which had on Sunday left the Philippines and was moving towards the southern islands of Okinawa and Tokyo in Japan on Monday.
He added that the focus of firefighting efforts in Riau over the next few days will be in Rokan Hilir, where satellites had picked up 162 fires between last Friday and Sunday. This was almost half of all the 338 fires detected across Sumatra and Kalimantan over the same three days.
A combination of dry conditions, sporadic rains and common incidents of illegal land clearing by burning last week had caused a spike in hot spots in Riau.
The fires led to a thick smoke hovering over Singapore and Malaysia, sending air pollution levels soaring towards unhealthy levels, igniting fears of a repeat of last year's record transboundary haze crisis.
While conditions in Singapore cleared up by Monday, a heavy haze continued to engulf most parts of Kuala Lumpur.
Xinhua news agency reported on Monday that air pollutant readings in the Malaysian capital were near unhealthy levels.
Figures from Malaysia's Department of Environment showed the readings of the Air Pollutant Index (API) at multiple monitoring stations in Kuala Lumpur reached 90 as of Monday afternoon, almost reaching the "unhealthy" level that is from 101 to 200.
Malaysia's API is determined mainly by measuring the amount of particulate matter with a diameter of less than 10 micrometres, or PM10 level. An API reading of 0 to 50 indicates good air quality while 51 to 100 means moderate.
The 88-storey Petronas Towers, the world's tallest twin buildings, were barely visible on Monday, said the Xinhua report, with the smoky haze reaching the office of Malaysia's Prime Minister Najib Razak, prompting him to post a tweet on his official twitter account saying: "The haze is back in some areas, please take healthcare measures, especially the old and the children."
Dr Sutopo said the fires in Rokan Hilir were mostly started on land owned by local farmers, and after a bout of rainfall - partly the result of cloud-seeding operations, conditions are expected to improve.
Some 7,200 firefighters have been deployed in Riau, together with six aircraft for waterbombing and cloud-seeding, Dr Sutopo had said last week.
Thousands of canals, reservoirs and wells have also been built to keep the ground moist and help prevent the fires from spreading.