His tent is a walk across a black wasteland pocked by the twisted wreckage of vehicles blown up in the war and little piles of human faeces left by the locals, who eschew latrines.

Many of them burn wood, waste and dung indoors for heating and cooking. The soot released into the air as a consequence is also a climate-changer because, being dark, it absorbs heat.

Also on the list are bloody diarrhea or stools that are black or tar colored.