Outside the city input. The reason for the rapid spread of Yulin epidemic is that it was imported from outside the city without timely prevention and control. Yulin, formerly known as Shang Jun, began in the Spring and Autumn Period and the Warring States Period and flourished in the Ming and Qing Dynasties. Yulin City is located in the northernmost part of Shaanxi Province, bordering the Yellow River and Shanxi in the east, Ningxia and Gansu in the west, Inner Mongolia in the north and Yan 'an in the south. Yulin is the main producing area of miscellaneous grains in Shaanxi. Rich in tourism resources, with world cultural heritage-Zhenbeitai, the first Great Wall in Wan Li, the top ten most potential ancient cities in China-Yulin Ancient City, Hongshixia, Tongwancheng Site, Hongjiannao and other major attractions. Yulin is rich in natural resources; Rich in energy and mineral resources, it is known as "Kuwait of China". There are Shenfu coalfield, one of the seven largest coalfields in the world, and Shaanxi-Gansu-Ningxia gas field, the largest comprehensive gas field found on land in China.