Yaan is located in the middle of Sichuan Province and the western edge of Sichuan Basin. It is adjacent to Chengdu, Meishan and Leshan in the east, Liangshan Yi Autonomous Prefecture in the south, Ganzi Tibetan Autonomous Prefecture in the west and Aba Tibetan and Qiang Autonomous Prefecture in the north. YaˇŻan covers an area of 15,046 km2. Mountain lands account for 94% of the total area and flat lands account for 6%. There are well-known mountains and rivers, including Jiajin Mountain, Erlang Mountain, Daxiang Ridge, Qingyi River, Dadu River, and Zhougong River. Yaan enjoys a subtropical monsoon mountain climate with significant vertical temperature changes. The annual amount of solar radiation is relatively low. YaˇŻan is abundant in rain with "heavy rain in summer, gentle rain in autumn and more rain in night than daytime", hence the name "City of Rain". The air quality is better than the secondary level in the national standard most of the time. The theoretical reserve of water resources of YaˇŻan is 16.01 million kWh. The forest coverage rate exceeds 60%, ranking first in Sichuan Province. Over 700 species of wild animals are living in YaˇŻan, including 19 species of national-level protected animal such as giant panda. Over 3,000 species of plants are distributed including dove tree, Cyathea spinulosa and other 10 national-level protected plants. Yaan is a prefecture-level municipality with the largest giant panda sanctuary in China.