Shanghai, China

Shanghai (上海; Zånhae in Shanghainese, Shànghǎi in Mandarin) is the most developed city in China, the country's main center for finance and fashion, and one of the world's most populous and important cities.

There are several ways to rate the size of cities; by the one Wikipedia uses, based on UN numbers, Shanghai is the third largest city in the world after Tokyo and Delhi. By any measure, it is in the top ten for the world and either the largest in China or second to Chongqing.