The problem occurs when smoke from forest fires combines with industrial pollution to create and acrid smog.
As well as being an environmental issue, the smog costs the region’s countries billions of dollars each year through lost working days and tourism.
Ministers gathering to discuss the problem in Malaysia this week said meteorologists were predicting that the cooling El Nina weather phenomenon would fade in the autumn, leading to a dry spell likely to herald a surge in forest fires which would in turn exacerbate problems with the haze.
Sam Bond