Malaysia has repeatedly ordered students to stay home as a health precaution as the current smog problem -- an annual dry-season occurrence -- has become one of the worst in years, exacerbated by tinder-dry conditions from the El Nino weather phenomenon.
Last week it had a enjoyed a respite from the acrid grey shroud that has sparked health alerts, sent thousands to hospitals for respiratory problems, and caused the cancellation of scores of flights and some major international events across the region.
On Friday, Indonesia launched its biggest operation ever to combat the crisis, with dozens of planes and thousands of troops battling the illegally started agricultural and forest fires in its territory on the huge islands of Sumatra and Borneo.
Thirty-two planes and helicopters -- including six aircraft from Singapore, Malaysia and Australia -- were deployed to back up more than 22,000 personnel on the ground.