Reuters: Wood and dung burned for home heating and cooking makes up most of a huge brown cloud of pollution that hangs over South Asia and the Indian Ocean during the winter months, researchers said on Thursday. The study in the journal Science solves the mystery of what makes up the soot in the brown haze linked to hundreds of thousands of deaths — mainly from lung and heart disease — each year in the region, they said. “Doing something about this brown cloud has been difficult …