The Great Liangshan Mountains located in the Ethnic Yi Autonomous Prefecture in southwest China’s Sichuan Province is an important passage of central China to the southwest border areas, as well as part of the ancient South Silk Road. The mountains, which height ranges from 2,000 to 3,500 meters, is the place where ethnic Yi people inhabit. In winter, dense fog blankets much of the high mountains and valleys for most of the day.