A new report from Open Observatory of Network Interference shows the Chinese government started blocking Wikipedia in all languages sometime in April of this year. The new block has expanded internet censorship in China, the Chinese language version of Wikipedia has already been blocked since 2015.
The move to block the site comes along with the 30th anniversary of the Tiananmen Square protests, that took place April 15, 1989 until June 4, 1989. The protests culminated in government troops massacring protesters on June 4, 1989.
China typically blocks specific web pages referencing the Tiananmen Square protests and massacre. China was not able to continue blocking Wikipedia after the site switched to HTTPS, making it effectively impossible to see the individual pages people are viewing.
The Wikimedia Foundation says it hasn’t received any notices about the block.