Known as Pingyang in the ancient time, Linfen was once the capital of China during the Jin Kingdom in the Warring States Period (476BC-221BC). During the Qin Dynasty (221BC-206BC), it belonged to the Hedong Shire, one of the forty-eighty shires of the nation. Many places in present Linfen had their names originated during the Sui Dynasty (581-618). There are Zhongtiao Mountain, Taiyue Mountain and Luliang Mountains in the east and west of the city. In the center stands the Linfen Basin. Mountains and hills are the main characteristic of the land, occupying about eighty percent of the city's territory. Fenhe River, one of the main branches of the Yellow River, flows through the city center. Research reveals that Linfen, located in the Chinese province of Shanxi, is the most polluted city in the world.