A couple of clarifications.
1. Chongqing is not the fastest growing city in the world. It is not even among the 20 fastest growing cities in China. See: http://www.newgeography.com/content/002873-chinas-top-growth-centers
2. Few "cities" are so misunderstood as Chongqing. The 32 million quoted population is for the provincial level municipality of Chongqing. This is simply a definition, not a "city" in any sense of the word. Chongqing’s population is more than one-half rural and little of it (less than 8 million) lives in the Chongqing metropolitan area. The provincial level municipality covers a land area similar to that of Indiana or Austria. Moreover, the provincial level municipality is losing population, with the 2010 census showing a population of 29 million. See: http://www.newgeography.com/content/002218-china-urbanizing-and-moving-east-2010-census