In spite of China’s intensifying crackdown on political dissent, residents still have plenty of leeway to air their environmental concerns and criticize polluters on social media, a new study shows.

Public appeals for action made on the social network Weibo reduced pollution violations at industrial plants by more than 60%, according to the study released this month by researchers from the University of Chicago and several other institutions.

Social media can still be an effective tool for some kinds of civic action in China, said Michael Greenstone, the study’s co-author and professor at the University of Chicago, in a news release. "The more popular the social posts are, the more effective they are in generating action from the government.”

The research was cofunded by the National Science Foundation of China and the Energy Policy Institute at the University of Chicago and has yet to be peer reviewed. The findings suggest that Chinese leader Xi Jinping’s government allows for greater civic debate on certain issues, and point to a way forward for activists in China seeking to promote their goals effectively and without running afoul of the authorities.

The study tracked real-time emissions data from almost 25,000 industrial plants across China. Once a pollution violation occurred, volunteers recruited from the general public sent messages to local authorities appealing for action.

Some of the messages were sent privately through government hotlines or online messaging platforms, while the others were delivered publicly via Weibo where the appeals could potentially be viewed by the platform’s 500 million users. The researchers also deliberately left some polluters out of public intervention in order to set a baseline.

While both forms of feedback led to improvements, the researchers found that public complaints via social media carried more weight. For instance, when citizens voiced their concerns over pollution through Weibo, the targeted companies reduced the level of lung-harming sulfur dioxide pollutants in the air by 12.2% compared with factories that hadn’t been targeted. By contrast, private complaints to a government hotline or website — even those using exactly the same wording — led to a marginal reduction in pollution, the paper said, without specifying by how much.

The researchers also found that social media posts with higher levels of engagement and visibility prompted law enforcement to take stronger action against polluters.

"The importance of the present study is to show, with its detailed quantitative analysis, the power that civil society can wield through public complaints and appeals on social media in effecting environmental reform,” said Daniel Gardner, a professor at Smith College and author of "Environmental Pollution in China: What Everyone Needs to Know."

"Even as the Chinese government becomes more authoritarian under President Xi, it’s still one, apparently, that displays a responsiveness to public sentiment, at least in environmental matters,” said Gardner, who wasn’t involved in the study.

Despite the study’s findings, not all public appeals against pollution are welcome. The authorities in recent years have removed Under the Dome and several other popular documentaries highlighting environmental causes from local Chinese streaming websites.

The researchers attributed the difference in government reactions to a simple factor: Who is taking the blame.

"In the case of pollution appeals, the central government set up these venues such as Weibo, WeChat, hotlines, and websites for citizen complaints partly in order to shift the blame to the local regulators,” Shaoda Wang, an assistant professor at the University of Chicago who co-authored the study, said via email.

However, Wang said, if "at times such citizen complaints could get out of control, and much anger would be directed toward the central government, the central government would censor some of the most visible complaints to avoid potential collective action.”

The study also noted that the public appeals appear to have lowered net emissions rather than simply driving pollution elsewhere. With civic engagement keeping both polluters and local officials on their toes, "the interventions might have created positive spillover effects,” according to the researchers.