Many domain names are blocked in mainland China under the country's Internet censorship policy, which prevents users from accessing certain websites from within the country.
A majority of apps and websites blocked are the result of the companies not willing to follow the Chinese government's internet regulations on data collection and privacy, user-safety, guidelines and the type of content being shared, posted or hosted.
This is a list of the most notable such blocked websites in the country. This page does not apply to Chinese territories that adhere to the policy of one country, two systems (Hong Kong and Macau).
ATTENTION: @Greg Bernhardt
Viewing post https://www.physicsforums.com/posts/7086547
I clicked on the link "USA" just below the image -- https://www.physicsforums.com/javascript%3AsetPOESUS()
and got this message:
Sorry, you have been blocked
You are unable to access physicsforums.com...