20 17 How many cities in China have subways?

By 20 17, the subway has been put into operation in the following 27 cities: Beijing, Tianjin, Shanghai, Guangzhou, Wuhan, Shenzhen, Nanjing, Chengdu, Shenyang, Foshan, Chongqing, Xi 'an, Suzhou, Kunming, Hangzhou, Harbin, Zhengzhou, Changsha, Ningbo, Wuxi, Dalian, Qingdao, Nanchang and Fuzhou.