According to NASA (Click the Picture to enlarge)
Thick haze collected in eastern China, south of Beijing, in mid-December 2007. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite took this picture on December 17, 2007. In places, the dull gray haze is thick enough to completely hide the land surface below. The haze appears confined to low elevations, only cresting the Taihang Shan Mountains in a few locations.
Here is a picture of a beautiful Chinese Sunset. (Don't stare you'll go blind.)