 A resurgence in subway use is being reported by almost a dozen significant Chinese cities, suggesting that the exit wave of Covid infections may have crested in several urban areas.Among the 11 cities reporting so are:Shanghai, Guangzhou, Shenzhen, and Nanjing All say they are seeing a rebound in trips over the last week. Beijing, Zhengzhou and Chongqing, and some others, have already reported increased subway usage and traff... 