We found a strong correlation between travel volumes departing from Wuhan, Hubei Province before the Spring Festival and the extent of amplification of the outbreak of COVID-19 in China in 2020, with 100 top cities. Almost 70% of exportations were within cities in Hubei province.
Keywords: 2019-nCov; Coronavirus; Public Health Emergency of International Concern; containment; migration; quarantine; travel.