Sudarsono is among more than 11,000 people treated for respiratory infections in Palangkaraya.

Sudarsono shuddered as he inhaled from an oxygen tank while being evacuated from his small house in Palangkaraya on Indonesian Borneo, yellow, acrid wildfire smoke billowing all around.

The 57-year-old fell sick after going out with three friends days earlier to fight fires creeping closer to homes on the outskirts of the city in Central Kalimantan province, one of the regions hit hardest by months of blazes and haze.

"I wore a mask, goggles, everything, but I was surrounded by smoke.…