It's winter in Beijing, and that means two things: cold and smog. Beijing has had freezing winter temperatures for thousands of years, but the smog is something new.

China first started experiencing serious air pollution in the 1970s, and by the 1990s Beijing was already one of the world's most polluted cities. Twenty years later, China still hasn't begun to solve its pollution problems.

The problem is serious. Beijing has spent much of this winter on yellow alert, a level of pollution that would be considered catastrophic in many other places but is business as usual in China. To avoid bad publicity, China rarely issues red alerts, even when smog levels warrant them.

This year the smog has been so bad that travel companies are reportedly offering "lung cleansing" trips to cleaner countries for those who can afford to escape for a week or two of fresh air.

When Chinese people have to choose between "fight or flight" in response to air pollution, the only rational choice is flight. Even the mildest pollution protests are met with a heavy police response.

For example, the city centre of Chengdu, the capital of Sichuan province in southwest China, was shut down in response to a simple prank: protesters had put face masks over the mouths of statues.

Anti-pollution face masks are ubiquitous in China, where people wear them to filter out fine particles in the air.

One man in Chengdu was even arrested for sharing a photo on social media. He allegedly claimed that the photo was a picture of a large crowd of environmental protesters. It was apparently a stock photo of a 2012 event.

World's worst

China's air pollution is notorious for being among the worst in the world, though India and Iran are catching up fast.

The World Health Organization says that 92 percent of the world's population breathes air that exceeds global pollution standards.

China is far from the only country dealing with rampant air pollution, but it is one of the most repressive.

Pollution protests are effectively banned. Local meteorological bureaus are prohibited from giving independent pollution advice that may conflict with the warnings issued by the central government.

And independent lawyers who sue to hold the government accountable to its own pollution regulations are routinely jailed, and in some cases lawyers have allegedly been tortured.

Yet China allows many other kinds of protests, even environmental protests against new chemical plants and power stations. In such cases citizens have been allowed to circulate petitions and stage demonstrations, some of which have even been covered on state media. Protesters can share photos of themselves marching to protest against local pollution, as long as it doesn't involve smog.

The Chinese government seems to have a relatively relaxed attitude towards such "not in my backyard" protests against air, water, and soil pollution. These are viewed as localised outbreaks of well-focused anger.

The inconvenient truth for China is that a billion individual actions won't solve China's pollution problem. Air pollution is a collective problem that can only be solved through coordinated government action.

A protest against a smokestack belching poisonous fumes into a particular neighbourhood is unlikely to spread across a city, never mind the country.

In a country that lacks a free media space, protests can even be used to gauge public opinion. If a project is unpopular, people will protest and their concerns can be addressed. If there are no protests, the project is allowed to go ahead.

Protests against smog are different. Everyone in China suffers from catastrophic air pollution. They can see it day in and day out, all over the country. A protest against smog in one city has the potential to spread like wildfire on national social media.

Any effort to complain about a problem such as air pollution that affects nearly everyone in the country is rapidly repressed by police and social media monitors.

China's inconvenient truth

For one week in March 2015 the Chinese government allowed its people to watch an environmental documentary that exposed Beijing's true pollution levels and the government corruption behind them.

The film, Under the Dome, is believed to have been watched by hundreds of millions of people before it was abruptly removed from the Chinese internet.

The timing was no accident: Under the Dome was made available during the annual session of the National People's Congress (NPC), China's rubber-stamp legislature. The theme of the 2015 NPC? The environment, of course.

The film, clearly inspired by Al Gore's An Inconvenient Truth, ends with the now-familiar list of things that "you" can do to save the environment: Take the bus. Ride a bike. Turn off lights. Call a government hotline to report suspected polluters.

Viewers were even encouraged to join one of China's 700-plus government-approved environmental organisations.

The inconvenient truth for China is that a billion individual actions won't solve China's pollution problem. Air pollution is a collective problem that can only be solved through coordinated government action.

Protests won't solve the problem either, but protests might spur the government to act. With no one to hold them accountable, China's rulers may waste yet another decade hoping the problem will just blow away. It won't.

Salvatore Babones is a comparative sociologist at the University of Sydney. He is a specialist in global economic structure.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial policy.