A black cloud over Cairo

Everyone could see the black cloud that forms over Cairo, but nobody knew its source. Not until former ACD doctoral candidate Heba Marey did some scientific sleuthing and solved the mystery. The source of the cloud turned out to be illegal burning of rice husks, done at night when farmers are less likely to get caught. Marey used NASA's Multi-Angle Imaging Spectroradiometer (MISR) to trace the path of the smoke plumes. More at NASA's Earth Observing System Data and Information System (EOSDIS)...