Singapore's environment agency advised people to reduce outdoor activity Monday as air quality worsened to unhealthy levels because of smoke from Indonesian brush fires that sharply reduced visibility and caused some to complain of stinging eyes and throats.
As of 3 p.m. local time (0900 GMT) the air pollution index had reached 127, in the "unhealthy" range above 100, according to the National Environment Agency's Web site.
"Persons with existing heart or respiratory ailments should reduce physical exertion and outdoor activity.The general population should reduce vigorous outdoor activity," the NEA said in its latest health advisory.
On Monday, the skies were so overcast that the skyline was nearly obscured and the sun appeared as just an orange ball through the haze. Air quality over the last two weekends has deteriorated into the unhealthy range, barely clearing up during the week, depending on the wind direction.
On Oct. 7, the index hit a nine-year-high reading of 150.
Singapore and Malaysia, which suffer the most from the haze, have called on Indonesia to swiftly ratify a regional treaty to fight cross-border haze, saying they would delay financial assistance if it does not.
Officials from Southeast Asian nations held a conference in Indonesia on Thursday to come up with measures to fight the fires and reduce the haze.
The dry-season haze has plagued Southeast Asia every year since the 1990s, stoking regional tensions and focusing attention on cash-strapped Indonesia's inability to enforce laws banning the practice.