JAKARTA, Indonesia Flights were canceled and drivers turned on their headlights in the daytime Sunday as a thick haze from Indonesia's illegal brush fires continued to sweep over large parts of the sprawling archipelago's Sumatra and Kalimantan provinces.


After hitting a nine-year "unhealthy" high on Saturday, air quality improved in Singapore on Sunday, while authorities in Malaysia also reported better conditions.

The thick smog Saturday prompted Singapore's environment agency to issue health warnings, saying people with heart or respiratory ailments should limit physical exertion outdoors, and the general population should "reduce vigorous outdoor activity."

In Malaysia, the skies were also clearer Sunday, after heavy smog brought the worst pollution level in years.

It was unclear whether the improvement was due to less smoke being produced in Indonesia or a change in wind direction.

Visibility was down to 50 meters (yards) in Central Kalimantan and West Kalimantan, on Indonesia's part of Borneo island. Flights were canceled in the three provinces of South Sumatra, Riau and Jambi.

"We had to cancel all flights to avoid plane crashes and for passenger safety," Basuki Mardianto, the head of Sultan Taha Airport in Jambi province, told The Associated Press.

The pollution monitoring index, measured in downtown Palangka Raya, the capital of Central Kalimantan, stood at "dangerous" as thick smoke penetrated windows and doors, forcing people to wear masks inside, the Antara state news agency reported.

Agung Catur, the head of the forest fire prevention unit, said peat soil blazes in the region were out of control and had worsened the air condition, Antara reported.

Malaysia, meanwhile, urged Indonesia to quickly ratify an agreement that would facilitate a regional response across Southeast Asia to the use of environment-damaging slash-and-burn methods by Indonesian farmers and plantation owners.

Indonesia is the only country among the 10 members of the Association of Southeast Asian Nations that hasn't ratified the ASEAN Agreement on Transboundary Haze Pollution, which the grouping approved in 2002.

"Only when Indonesia ratifies this agreement can member countries set up (the) center so that prevention and extinguishing of fires can be done easily," Malaysian Environment Minister Azmi Khalid told The Sunday Star newspaper.

Azmi called on Indonesia to prosecute any plantation company or farmers found responsible for lighting brush fires. "We implore Indonesia to impose the most severe penalties under their law to anyone found guilty," he said.

In Singapore, the National Environment Agency reported an air pollution reading of 34 — which it rates as "good" — on Sunday after it soared to a nine-year-high of 150 on Saturday.

In Malaysia, the air was also less polluted, the Department of Environment said, with six of Malaysia's 51 monitoring stations recording unhealthy air quality, compared to 21 on Saturday.

The highest reading of 141 was registered in the southern city of Johor Bahru, near Singapore. The official Air Pollutant Index designates readings of above 100 as unhealthy.

The worst case of smoke-induced haze in Southeast Asia occurred in 1997-98. It blanketed much of the region and was blamed for losses of nearly US$9 billion in health and business costs and lost tourism.