As of Sept. 18, 2019, the Chinese government is blocking access to Proton VPN as part of a larger crackdown on Internet freedom.
The Chinese government works hard to control its citizens’ access to the Internet. The Great Firewall employs a vast system of technical tools, including DNS filtering, URL filtering, and deep packet inspection, that the Chinese government uses to prevent people in China from accessing foreign websites. The government also uses these tools to detect and block VPN servers.
We are investigating the situation and working on countermeasures that will help us circumvent government blocks in the future.
Tor is the most effective way for people in China to access blocked content. To bypass the Great Firewall, you will need to use a Tor bridge, or a special unlisted Tor server. Because they are unknown, the Chinese government cannot block their IP address. To evade deep pack inspection, Tor has created pluggable transports that mask Tor traffic, making it look like standard Internet traffic.
The Tor Project has a Tor bridge guide to help you set up a secure Tor connection.
Updated Sept. 18, 2019