A pool of air pollution has spread out over eastern China and then slipped over the coast like water over a dam. A river of haze flows across the East China Sea past the Korean Peninsula and northeastward toward Japan, where it arcs along the western coastline of the island chain before disappearing out of the scene at upper right.

Skies over China have darkened in the past five decades, thanks to a nine-fold increase fossil-fuel emissions. In January 2006, Yun Qian and collaborators reported this finding in Geophysical Research Letters. According to the Associated Press, Qian stated that pollution absorbs and reflects sunlight, allowing less of it to reach China’s urban areas.