China is directing 2,000 industrial companies to shut obsolete factories to meet national energy intensity targets. Five years ago, Beijing pledged to cut by a fifth its industry's energy intensity, a measure of energy consumed by unit of output. That goal looks in jeopardy, mainly because the $586bn stimulus package rolled out in 2008 favoured China's biggest and dirtiest industries. In the aftermath of the Lehman shock, China chose growth over the climate. Now the panic is over, there are tentative signs that it is planning another push to improve the efficiency of its smokestack economy. That is to be welcomed, so far as it goes.

Measuring energy intensity was much criticised in the run-up to the Copenhagen summit on climate change as a poor substitute for setting overall emissions targets. In fact, as the Japanese have argued, there is much to be said for focusing on how much energy individual industries use, a bottom-up approach that can be more practical than setting grandiose (sometimes unattainable) goals.

In China's case, the problem is implementation. In practice, far from the eyes of the planners in Beijing, many party cadres have favoured growth and job creation, and left environmental improvements for another day. Nor are Chinese data on energy use – surprise, surprise – entirely trustworthy. Recent statistical revisions make it easier for industry to meet its five-year target. There are even suggestions that the recent crackdown is not all it seems. Some of the factories slated for closure have already stopped producing.