Volunteers from the Blue Sky Rescue team disinfect at the Qintai Grand Theatre in Wuhan, Hubei province, the epicentre of China's coronavirus disease (COVID-19) outbreak, April 2, 2020. Volunteers in hazmat suits have been spraying Wuhan with disinfectant to help the Chinese city where the coronavirus first took hold get back to work as the number of new cases in China drops. REUTERS/Aly Song

Volunteers from the Blue Sky Rescue team disinfect at the Qintai Grand Theatre in Wuhan, Hubei province, the epicentre of China's coronavirus disease (COVID-19) outbreak, April 2, 2020. Zhang Quan is a member of Blue Sky Rescue, China's biggest nonprofit civil rescue organization, which has been involved in helping distribute medical supplies for the epidemic. REUTERS/Aly Song

A volunteer from the Blue Sky Rescue team disinfects at the Qintai Grand Theatre in Wuhan, Hubei province, the epicentre of China's coronavirus disease (COVID-19) outbreak, April 2, 2020. The former soldier leads a team of 60 volunteers that has been focused on disinfecting places such as hospitals and schools. REUTERS/Aly Song

Volunteers from the Blue Sky Rescue team disinfect at the Qintai Grand Theatre in Wuhan, Hubei province, the epicentre of China's coronavirus disease (COVID-19) outbreak, April 2, 2020. REUTERS/Aly Song

Volunteers from the Blue Sky Rescue team disinfect at the Qintai Grand Theatre in Wuhan, Hubei province, the epicentre of China's coronavirus disease (COVID-19) outbreak, April 2, 2020. REUTERS/Aly Song

Volunteers from the Blue Sky Rescue team disinfect at the Qintai Grand Theatre in Wuhan, Hubei province, the epicentre of China's coronavirus disease (COVID-19) outbreak, April 2, 2020. REUTERS/Aly Song