Many schools in Singapore and Malaysia were closed on Tuesday as worsening haze from huge forest fires in Indonesia threatened the air quality across large areas of South East Asia.
Several flights were also cancelled due to the smog caused by slash-and-burn agricultural practices in Indonesia's Sumatra and Kalimantan islands, which have become an annual issue for its neighbors.
Air quality stations recorded unhealthy air levels early on Tuesday as the thick, dirty white haze blanketed large parts of the region.
Organizers of this weekend's Singapore grand prix say they're monitoring the situation amid concerns the smog could cause visibility issues for drivers and spectators.
Malaysia was due to begin cloud-seeding operations, where chemicals are released into the air from a plane, to help produce rain. Indonesia has already dispatched aircraft to carry out similar measures, while more than 1,000 troops have been sent to Sumatra island to help extinguish the fires.
Indonesia's Riau province declared an emergency after its air pollutant index hit extremely dangerous levels. Health stations were set up to treat those suffering from respiratory problems.
This year's smog has been exacerbated by the El Nino weather phenomenon, causing a prolonged dry season, which has fanned the flames.
Environment campaigners blame the illegal burning of peatland and forests for the annual spell of severe haze and dangerous air quality levels.
Persistent calls for firm action to be taken against the large agricultural firms who set off the huge fires to raze large areas of forest have fallen on deaf ears.
As in previous years, Indonesian President Joko Widodo has asked authorities to take strict legal action against those causing the fires. Measures would include revoking their land permits, he said.
But big profits for plantation owners, along with corruption and collusion by local officials means that little is done, according to forestry researchers.
Officials hope the monsoon season, which is due at the end of September, will help clear the haze.
mm/jil (AP, AFP, Reuters)