Beijing has some seriously bad air. How bad? On a scale of 1 to 500, the United States Environmental Protection Agency says anything over 100 is unhealthy and anything above 400 is an emergency. Recently, the pollution index for Beijing hit 755. For purposes of breathing, it's like being downwind of a forest fire while smoking a cigar.

China's communist rulers normally suppress news like that. In 2009, when the U.S. embassy in Beijing started putting air quality numbers on its Twitter feed, the government demanded in vain that it stop.

But when your air contains enough foreign matter to mold bricks, it's hard to claim the sky is blue. And lately, the authorities have decided censorship of the topic is futile.

"I've never seen such broad Chinese media coverage of air pollution," a Beijing consultant named Jeremy Goldkorn told The New York Times. "From People's Daily to China Central Television, the story is being covered thoroughly, without trying to put a positive spin on it." In November, the outgoing president actually acknowledged the need to combat environmental destruction.

Pollution is not the only detectable thing in the Chinese air lately. This month, after the government interfered with an editorial in a national newspaper based in Guangzhou, protesters mounted some of the boldest demonstrations since the 1989 Tiananmen Square movement—while for several days, police stood by and let them.

Chants were heard that ordinarily could have brought harsh punishment: "Down with the Communist Party!" Unlike Tiananmen, these didn't end in mass bloodshed. The newspaper whose staffers had threatened to strike was not closed down.

Almost unnoticed amid all this was a report by the official news agency that the government plans to dismantle its notorious system of "re-education through labor," where petty criminals, religious people, and dissidents have often been imprisoned without trial. "If it can be abolished this year, I think it's an extremely important step toward rule of law," Peking University law professor He Weifang told Reuters.

That may be expecting too much. At least since 1989, human rights advocates have hoped China would soon evolve into a freer, more democratic society, but so far they have always been disappointed.

The 2008 Beijing Olympics were supposed to push the government toward openness and tolerance. Instead, the artist who helped design the famous "Bird's Nest" stadium, Ai Weiwei, wound up in detention for making noise about official abuses. In 2011, the government mounted a particularly brutal offensive against malcontents.

But authoritarian governments don't last forever, and this one faces changes it can't control. Back in 1996, Asia scholar Henry Rowen of the Hoover Institution at Stanford University noted that when countries reach a per capita income level of $8,000 (unless the money comes mostly from oil), they invariably become freer. Given China's pace of economic development, he predicted that it would become a democracy "around 2015."

When I called him the other day to ask about that forecast, Rowen sounded optimistic. Ever-growing incomes and a growing middle class are not the only stimuli for positive change, he noted: "Rising education levels also predispose people to voice their views on things that affect their sense of justice or that directly affect their lives."

Because of the rise of capitalism in China, the country's people have gained a large measure of freedom—in such critical matters as where they work, where they live, and where they may travel. The sphere of personal autonomy is vastly larger than it was in the dark days of Mao Zedong.

Technology holds promise. "The blogosphere is a very lively place, and it's huge," he says. "The censors have an impossible job to shut off things they don't like." People unhappy with the government can now easily find others who agree and mobilize to spread the word.

Chinese have also taken to traveling abroad—particularly to Taiwan, which has fiercely contested elections, an aggressive press, and wide-open debate. It's living proof that democracy can develop in China without disastrous social upheaval or mass violence.

It's no surprise that the Communist Party thinks it can prevent such change on the mainland. Autocratic regimes rarely leap at the chance to empower the citizenry. But this one is not exempt from the powerful forces unleashed by China's transformative economic miracle.

The Communist Party insists the old dictatorial system works fine for a modern society. It's a familiar message, but somehow, the Chinese are choking on it.