Beijing, July 21, (dpa/GNA) - After nine coronavirus cases were confirmed among employees at Nanjing airport the eastern Chinese city cut more than 300 flights on Wednesday.
More than 100 flights were already cancelled a day earlier, authorities reported.
Mass testing was taking place in four areas close to the airport.
Anyone who wants to leave the city of 8 million people must show a negative coronavirus test.
The airport infections were registered during routine testing and the employees went into quarantine. Further workers were then tested.
China has largely kept the virus under control since its initial outbreak in early 2020 and has only had limited local outbreaks since.
At the moment the south-western province of Yunnan is struggling with infection numbers. It borders Myanmar, which has been hard-hit by Covid-19.
Dehong prefecture is particularly affected, with 267 people in hospital, Xinhua news agency reported.
Among the infections were 82 local transmissions. Thirty-one asymptomatic infections were also reported.
Life has largely returned to normal in China, where the world's first infections with the new viral disease were detected in December 2019.
Authorities have a strict "zero-Covid" policy, and outbreaks trigger mass testing, exit restrictions, contact tracing and quarantine.
Tough restrictions are also in place for those entering the country. They must spend at least two weeks in a quarantine facility.
A high border fence has been erected along parts of the border with Myanmar.