The World Health Organization (WHO) hopes to find answers to the origins of the coronavirus.
The idea was originally to arrive in China in early January, but after a visa dispute, that schedule broke.
The delegation with a number of experts is now in place in Wuhan, where the virus was discovered at the end of 2019. But the first thing that awaits them is quarantine - for two weeks.
However, two of the delegation are in Singapore after antibodies were found with them and therefore they have not been admitted to China.