One of those people travelling from Moscow had the Delta variant of COVID-19. After they left the plane, staff from the Nanjing Lukou airport swooped in to pick up their rubbish.
According to Chinese officials, when those cleaners exited the aircraft they brought the virus along with them to the outside world - sparking what has now become China's widest outbreak since Wuhan.
In the last few weeks, at the height of the summer travel season, Delta has been detected in at least 16 Chinese provinces and municipalities. Most cases are linked to Nanjing.