After new corona virus infections were discovered in Shanghai, China cancelled hundreds of flights, closed some schools and suspended tourism activities, putting pressure on this Winter Olympics host country.

China wants to reduce pollution risks at all costs and to adopt a health policy aimed at preventing any injury, a few months before the Beijing Olympics kicks off on February 4.

To that end, China resorted to strict restrictions on those wishing to enter its territory, and imposed a mandatory health stone and extensive screening as soon as a few injuries arose.

All movements are closely monitored through mobile applications, which allows for the identification of cases of mixtures.

According to local authorities, three friends who travelled together throughout Shanghai last week were found infected with the corona virus and all had received the vaccine.

To prevent HIV transmission to other regions, more than 500 flights were cancelled from the airports of China's economic capital.

The Shanghai municipality also suspended all tour group trips to the nearby city of Suzhou visited by the three injured.

Suzhou, with a population of about 13 million, is well known for its imperial channels and gardens. The city has closed its tourist sites and is now requesting a test showing that people wishing to go to another area are not injured.

In the greater Shanghai region, a quarantine was imposed on a campus after a staff injury was monitored, according to official newspapers.

China announced Friday that it had registered 13 new COFID-19 infections on its territory the previous day.