A new cluster of infections in Beijing has seen authorities raise the coronavirus alert level, cancel flights and roll out mass testing. The WSJ’s Jonathan Cheng explains how the outbreak threatens China’s economic recovery and virus eradication efforts. Photo: Chen Zhonghao/Zuma Press HONG KONG—Chinese officials cancelled hundreds of flights in and out of Beijing, restricted movement and renewed closures of businesses and schools as they battled to contain a fresh wave of new coronavirus cases in the nation’s capital. Health officials on Wednesday reported 31 new confirmed cases in Beijing for Tuesday, bringing the city’s six-day total to 137 since the most recent cluster of infections first emerged on June 11—most of which are tied to Xinfadi, a sprawling meat and vegetable wholesale market in Beijing’s…