THE city of Beijing got worldwide attention last weekend as its readings for air pollution soared to unconscionably high levels, even for the usually smog-smothered residents of the Chinese capital. By mid-week readings had receded from “beyond index” to merely “hazardous”. But by then Shanghai was grappling with its own bout of abnormal pollution.

China’s crisis in air quality is indeed a national one. This month dozens of other cities, from Shandong province in the east to Guizhou in the south-west, recorded pollution spikes. Experts attribute this to an exceptionally cold winter that has caused more burning of coal and other fuels than usual, to temperature inversions over some places, and to unfortunate wind patterns in others.

Even in the absence of such spikes, air quality in much of China routinely fails to meet basic standards laid down by the World Health Organisation (WHO). The smallest and most dangerous particles are called PM2.5 because they measure 2.5 microns or less in diameter, fine enough to enter deep into the lungs and into the bloodstream. The WHO deems 25 micrograms of such matter per cubic metre of air to be an achievable and acceptable level. In Beijing, readings hit nearly 1,000 micrograms.

The health impact is vast. Tens of thousands of Chinese are reckoned to die each year because of foul air. For instance, in the past three decades, coinciding with a mad dash towards growth and industrialisation, China has seen a more than fivefold jump in mortality rates for lung cancer. John Cai, director of the Centre for Healthcare Management and Policy at the China Europe International Business School (CEIBS), says rates of smoking, which might have explained this, have not risen dramatically.

The economic impact is large, too. Tourists kept away last week, even if sellers of masks did a roaring trade. Beijing ordered production to be halted at polluting enterprises and on construction sites. Flights were cancelled and travel in government cars was banned (though perhaps this improved productivity).

Splutter and cough

Now officials must contend with the political impact of bad air. China’s government has long staked its legitimacy on being able to generate improved standards of living, and people have grown used to complaining about things they do not like. Adding chronically poisoned air to the mix could prove volatile, some think.

Dai Qing, a veteran environmental activist, says that the angry reaction to this month’s extreme pollution shows that the issue now overshadows other pressing problems such as corruption and infringements on people’s liberties. “For years, we environmentalists have been telling the authorities that GDP growth at any cost is a mistake,” she says.

The authorities deserve credit for some initiatives, such as improved standards for vehicle and factory emissions, converting urban-heating systems from coal to gas, and investing in sources of renewable energy. Improving air quality is a long-term project. Western cities took decades to clean their air.

However, authorities must also shoulder blame for not taking the problem seriously enough. For years they persisted in underreporting levels of pollution. The American embassy in Beijing has long irritated the government by monitoring pollution and publishing the results hourly. Last year China asked the Americans to desist, but was rebuffed. Among ordinary Chinese, the service is extremely popular.

Despite the methodological shortcomings of this single-point monitor, the independent readings have led the authorities to release more detailed data. In 2012 the Beijing municipal government began reporting PM2.5 data for the first time. And from the start of this year, the country’s environment ministry announced, 74 cities around the country were to begin monitoring and reporting on all sorts of pollutants, including PM2.5, sulphur dioxide, carbon monoxide and ozone.

These moves, combined with the state media’s criticism of this month’s pollution, suggest that the authorities are having to abandon the idea of downplaying the problem. Newspapers and broadcasters, some of them usually cautious, have reported prominently just how severe and intolerable the pollution is. Mr Cai of CEIBS says the episode should come as “a serious warning” to the government that it must begin taking radical action.