WHEN, in 2008, the American embassy in Beijing started publishing a measure of the fetid smog enveloping the capital, China’s government protested and ordered the publication to stop. Its instinct was to sweep unwelcome facts about the nauseating level of pollution in the country under the carpet. Now that seems to be changing. New rules on pollution say that official data, formerly held secretly, should be published. It is an important step, not just for China’s environment, but also because it gives new power to the large and growing movement of citizen activists who have been lobbying for the government to clean up.

China is now emitting almost twice as much carbon dioxide as the next-biggest polluter, America. At current rates, it will produce 500 billion tonnes of carbon dioxide between 1990 and 2050—as much as the whole world produced between the start of the Industrial Revolution and 1970. Pollutants in the air in Beijing have hit 40 times the level decreed safe by the World Health Organisation. Yet China did not have a ministry devoted to environmental protection until 2008, and the government has done its best to keep information about the levels of filth in the air and water under wraps. Even now, the state is keeping secret a nationwide survey of soil pollution.

The new rules that have just come into effect signal the beginning of a move towards openness. They require 15,000 enterprises, including some of the biggest state-owned ones, to make public in real time details of their air pollution, waste water and heavy-metals discharges (see article). In the past, polluters gave the data on their emissions only to the government. In future NGOs such as the Institute of Public and Environmental Affairs, run by Ma Jun, a former investigative journalist who has been badgering the government on green issues for years, will get these data to analyse and publicise as they wish. Things are opening up at a local level, too. In 2012 only a few cities, including Beijing, published statistics on air quality. Now 179 do. And more firms are volunteering information about pollution—especially those that need foreign investors.

Unwilling liberals

The impetus behind this new transparency is not a sudden enthusiasm for liberalism. Rather, the government is worried that people are increasingly angry about pollution—a recent Pew survey of the concerns of Chinese citizens found that pollution was fourth, behind inflation, corruption and inequality, but was rising fast—and attempts to clean the country up by central-government fiat are foundering.

The government sets a national target for carbon-dioxide emissions per unit of GDP. It determines how much coal may be burned. It requires companies to install certain pollution-control devices. But all these rules—like most Chinese environmental controls—operate through the central-planning system. And that system is subject to “regulatory capture”—getting nobbled by the enterprises it is supposed to control and by the local governments who own or influence them. Factories evade targets by, for example, operating illegally at night, or by dissolving carbon-dioxide or sulphur emissions in water—and then dumping the toxic brew in the local water supply.

More public disclosure will not, by itself, end such baleful practices. But by exposing levels of pollution to public scrutiny, it will allow people to make better-informed choices, to lobby factories and officials for change and to keep an eye on the implementation of environmental laws. The new rules should thus expose polluters to a scissor-style pressure: from above, through the central-planning system, and from below, from the media and organisations such as Mr Ma’s.

Much more is needed. Cracking down on polluters will require provincial or city governments to fine them or take them to court—which they will be reluctant to do, since they often own them. The new disclosure rules have only milk teeth, not real bite. They talk, for example, merely of “urging” enterprises to fulfil “due responsibilities”. And, just as the government is encouraging bottom-up activism on environmental matters, it is cracking down on China’s hyperactive microbloggers.

This points to a tension at the heart of China. The government is nervous of active citizens, yet it needs them. If it gives them more freedom, they can be more useful; if it suppresses them they may be easier to control. These new environmental rules are a move in the right direction. For China’s sake, may there be many more.