Cited from "Study in the Czech Republic" (https://www.studyin.cz/)
As of 1 September, it is compulsory to wear a facemask or similar protective respiratory equipment in given places listed in the infographics below. The measure becomes effective from 1 September until the cancellation. Wearing masks will be mandatory universally only at locations with the highest epidemiological risk. You can read more about the high-risk areas on the website of the Ministry of Health. It is also recommended to wear a mask wherever there are many people and a safe distance cannot be maintained.