A national flag flies in the hazy, foggy sky at a primary school in Jinan city, Capital of East 皇冠体育app's Shandong province on Jan 14, 2013. [Photo by Zheng Tao /Asianewsphoto]

Students do their exercises between classes in a classroom instead of outdoors at a primary school in Jinan city, Capital of East 皇冠体育app's Shandong province on Jan 14, to prevent students from exposure to the threat of dense pollutants floating in the air due to the heavy fog and haze. [Photo by Zheng Tao /Asianewsphoto]