Mongabay: Air pollution caused by fires set for land-clearing on Sumatra has become a regularly occurrence in Southeast Asia, spurring hand-wringing in Singapore and Malaysia over health effects and worries among environmentalists over the climate impacts. While these fires are often termed "forest fires", the reality is much of the area that burns each year has already been deforested and today mostly consists of grass, scrub, and remnants of what was once forest. But the impacts are nonetheless very substantial,...