Kunming is the capital of Yunnan Province in China.Known in China as the "City of Eternal Spring" (春城, Chūnchéng), Kunming lies at an almost-tropical latitude but its 2000 m (6600 ft) altitude gives it a very temperate climate. It may snow in winter and locals says the recent winters have become colder and colder, so pack warm if visiting from December to February. Rainy days are also usually cold. The air is also quite clean compared to many Chinese cities, but the population of the prefecture is closing on 10 million and the city is expanding rapidly, with modern buildings and numerous highways emitting their fair share of air pollution. In addition to its own charms, Kunming also serves as a hub from which to explore Yunnan Province.