China is not a country known for bending to the whims of its populace. But as the country’s breakneck economic growth slows, public outrage has escalated over a pollution crisis that closed schools for days and sent thousands to the hospital in December. Beijing’s smog has become political.
The Communist Party appears to be going to lengths to diffuse the criticism. Beijing’s mayor said last year that if the air wasn’t improved by 2017, he’d cut off his own head. President Xi Jinping has said he checks the air pollution levels every morning. “The central government talked about GDP before,” says Wang Yongchen, one of the country’s most prominent environmentalists. “Now there are too many dangers.”
Compounding the public outrage: Smog data today is publicly available. The U.S. embassy in Beijing began releasing readings of PM2.5—the tiny carcinogenic pollutants that cause smog—in 2008. Four years later, Beijing released its own readings, and local governments followed suit. Under the Dome, an investigative documentary about pollution that mined that data, got 100 million online views (and sent green company stocks soaring) this summer, before censors banned it.
The country’s December pollution crisis lasted 53 hours and was lifted after strong winds cleared the clouds away. Mistrust of officials lingers still.
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A version of this article appears in the January 1, 2016 issue of Fortune.