More heavy smog is forecast to hit North China in the coming days, not long after it was previously blanketed by severe air pollution. It underlines the government still has to solve this seemingly intractable environmental problem.

There are few issues that do more disservice to the credibility of the governance capability of the authorities than the failure to protect residents from exposure to polluted air, given the smog's severe consequences, both medically and socially.

Air pollution has been blamed for the sharp rise in lung cancer cases in China, by five times over the past 30 years, which has made it the top killer among all cancers in the country.