I made an error. The 155 million is the number of
outgoing tourists: the number of Chinese visiting other countries. The number of
was 145 million in 2019. I probably had too many pages open and had the outgoing numbers confused with the incomings.
But how would China determine which country released the bio agent? Only total certainty about the source can justify nuclear retaliation. Fortunately, the total COVID-19 bungle in the US demonstrates that US bioweapons would probably hurt the US far worse than China.
Hotels are poor for quarantine, as most of them have just one internal air cirulation system. If even one occupant is infected, the virus particles can spread thoughout the building. Good quarantine requires an independent cirulation system for each suite; that is expensive and therefore uncommon.