Didi Kuaidi says it hosts over 4 million rides a day in China, and controls over 80 percent of that country's private carng market. Just last month, Kalanick said that Uber has managed to control around 30 percent of that market. Uber says that around 30 percent of the company's global rides originate from its China branch. In fact, the southwestern city of Chengdu (population: 5 million) is, according to Uber, its No. 1 city.