Chinese censors have blocked social media activity in China related to a 2015 crackdown on human rights lawyers, new research shows.

Since July 9, 2015, more than 250 Chinese rights lawyers, legal staff, activists, and their relatives have been detained by public security agents in China, known as the 709 Crackdown. Researchers say keywords related to the 709 Crackdown have been blocked on Weibo and WeChat – two of the most widely-used social media networks in China.

The names of the individual human rights lawyers detained in the crackdown with a combination of other keywords were blocked on WeChat, according to a report published by the University of Toronto’s CitizenLab on April 13. In addition, 58 images related to the event were blocked – specifically infographics, profile sketches of the detained lawyers and images of people holding protest signs.

Separately, 60 keyword combinations have been blocked on Weibo Search. Keywords such as 709, rights lawyer, human rights or the name of detained lawyers in combination with other keywords such as arrest, torture, interrogate, lawsuit and mass arrest have all been blocked.

“Our report serves as a reminder that for a large portion of the world, social media act as gatekeepers of what they can read, speak, and see. When they operate in a repressive environment like China, social media can end up surreptitiously preventing important political topics from being discussed,” said CitizenLab's Professor Ron Deibert in a blog post launching the report.

The research was a part of ongoing monitoring on censorship in China.

“We live in a world in which our choices and decisions are increasingly determined by algorithms buried in the applications we use,” Deibert wrote. "Our research aims to break through that obfuscation and bring such algorithms to account."

Watching the watchers

Researchers registered a Chinese phone number and Canadian phone number to separate WeChat accounts. They then sent messages containing keywords and images related to the 709 Crackdown between the two accounts to determine the blocked keywords.

Censorship was only enabled for accounts registered to phone numbers based in China. China-focused, simplified Chinese-language daily news yielded the most censorship results on WeChat, whereas Weibo appears to block both traditional and simplified Chinese.

“This censorship is implemented in ways that are not transparent to users, a continuation of trends we have seen in past research,” researchers said.

As of Feb. 16, four lawyers and activists have been convicted on charges associated with the 709 Crackdown, 10 others have been formally charged with various offenses, and an additional 10 have been released pending further investigation or released on bail. China’s crackdown extends beyond mainland Chinese citizens to include Hong Kong booksellers, foreign NGOs based in China, and foreign human rights activists.

“The 709 Crackdown is considered one of the harshest systematic measures of repression on civil society undertaken by China since 1989, and is the subject of much ongoing international media and human rights discussion,” Deibert wrote.

The Great Firewall

China has been actively supervising and regulating online speech for nearly two decades.

The Chinese Communist Party, which enforces some of the world’s most restrictive media censorship practices, has long argued that its control of information is important for continued social stability.

In addition to filtering information circulated online, the government produces fake comments in a bid to influence and control internet discussions.

A study led by Harvard University scholar Gary King showed that Beijing writes approximately 488 million social media comments a year — most praising the regime in Beijing.

Reporters Without Borders, a non-government organization which tracks press freedoms around the world, ranked China 176th in the 2016 World Press Freedom Index.

It says that in addition to “building a Great Firewall to monitor and control blogs and social networks, the Communist Party exercises total control over China’s many media outlets.”

Editor: Edward White