Droplets of oil fell from the toxic clouds on the town south of Mosul, leaving a sooty residue on clothing, houses, crops and even livestock.

A bookstall vender frantically tried to close up shop before a wave of sooty tear gas engulfed him and his kiosk.

But early stoves didn't generate sufficient heat to quickly cook food, and they spewed too much sooty smoke, making inside use unhealthy and dangerous.