The eastern city of Nanjing in China is facing a dangerous outbreak of COVID-19, the worst one after Wuhan. Authorities have set up checkpoints and suspended flights till mid-August. 170 people have been diagnosed with the Delta variant in 10 days in Nanjing and surrounding regions of Anhui, Liaoning, Sichuan and Guangdong. Mass testing is being done for the second time for 9.3 million people in Nanjing this week. Some public transport has been suspended while taxi drivers have been instructed to not leave the city limits. Other cities in the region have suspended road passenger transport with Nanjing while checkpoints need the health code status of people traveling from Nanjing. This is the third outbreak of the Delta variant in China after Yunnan and Guangdong in May and June. Some of the confirmed cases are people who were part of a crowd of 2000 in Zhangjiajie at a show.They are now spread across China. Authorities are concentrating on cleaners, who might have contracted the virus while cleaning planes and then passed it to friends and family. Officials of the Chinese Communist party are criticising the airport authorities for negligence and not separating operations of international and domestic flights.