Chongqing, Chongqing Municipality, China

Chongqing, with over 100 days of fog per year, is also known as the "Fog City" (雾都), and a thick layer of fog shrouds it for 68 days per year during the spring and autumn. During the Second Sino-Japanese War, this special weather possibly played a role in protecting the city from being overrun by the Imperial Japanese Army.
According to the National Environmental Analysis released by Tsinghua University and the Asian Development Bank in January 2013, Chongqing is among one of the ten most air-polluted cities in the world. Also according to this report, seven of the ten most air-polluted cities are in China, including Taiyuan, Beijing, Urumqi, Lanzhou, Chongqing, Jinan and Shijiazhuang.