A father feeds water to his son next to his daughter in a train during the annual Spring Festival travel rush ahead of the Chinese Lunar New Year, in Luohe, Henan province, China January 14, 2020.

An employee stands behind a door as the train arrives at a railway station while the annual Spring Festival travel rush begins ahead of the Chinese Lunar New Year, in Baoding, Hebei province, China January 10, 2020.

Passengers wearing masks are seen at the waiting area for a train to Wuhan at the Beijing West Railway Station, ahead of the Chinese Lunar New Year, in Beijing, China January 20, 2020.

Performers wear costumes for the arrival of Chinese tourists at Suvarnabhumi Airport during a welcome ceremony of Chinese Lunar New Year travellers in Bangkok, Thailand January 22, 2020.

Travellers wait for their train at a railway station as the annual Spring Festival travel rush begins ahead of the Chinese Lunar New Year, in Beijing, China January 10, 2020.

People walk outside Beijing Railway Station during the annual Spring Festival travel rush ahead of the Chinese Lunar New Year, in Beijing, China January 20, 2020.

Paramilitary police officers wearing masks are seen at Shanghai railway station in Shanghai, China January 22, 2020.

Travellers wait for their train at a railway station as the annual Spring Festival travel rush begins ahead of the Chinese Lunar New Year, in Beijing, China January 10, 2020.

A man pushes his luggage as a child sits atop with a mask at the Beijing West Railway Station, ahead of Chinese Lunar New Year, in Beijing, China January 20, 2020.

Passengers wearing masks are seen on a train at Shanghai railway station in Shanghai, China January 21, 2020.

A passenger wears a mask at Shanghai railway station in Shanghai, China January 22, 2020.

Travellers line up to board their train at a railway station as the annual Spring Festival travel rush begins ahead of the Chinese Lunar New Year, in Shijiazhuang, Hebei province, China January 10, 2020.

A traveller pushes his luggage as his son rides atop, in Beijing West Railway Station during the annual Spring Festival travel rush ahead of the Chinese Lunar New Year, in Beijing, China January 13, 2020.

A staff member wearing a mask monitors thermal scanners that detect temperatures of passengers at the security check inside the Hankou Railway Station in Wuhan, Hubei province, China January 21, 2020. Picture taken January 21, 2020. China Daily via REUTERS

Passengers wearing masks are seen at Hongqiao International Airport in Shanghai, China January 20, 2020.

A woman wearing a mask is seen at a waiting area for a train to Wuhan at the Beijing West Railway Station, ahead of Chinese Lunar New Year, in Beijing, China January 20, 2020.

A woman holding a rat stuffed toy sits inside a train as the annual Spring Festival travel rush begins ahead of the Chinese Lunar New Year, at a railway station in Beijing, China January 10, 2020.

Image used for illustrative purpose. Passengers wearing masks walk under a train information board at the Beijing West Railway Station, ahead of the Chinese Lunar New Year, in Beijing, China January 20, 2020.

A boy takes a nap in a train as the annual Spring Festival travel rush begins ahead of the Chinese Lunar New Year, in Shijiazhuang, Hebei province, China January 10, 2020.

Travellers wait for their trains inside Zhengzhou East Railway Station during the annual Spring Festival travel rush ahead of the Chinese Lunar New Year, in Zhengzhou, Henan province, China January 13, 2020.

Chinese tourists wear masks as they arrive at Suvarnabhumi Airport during a welcome ceremony of Chinese Lunar New Year travellers in Bangkok, Thailand January 22, 2020. Image used for illustrative purpose