A stone lion on a bridge in Tianjin is covered with a mask in the heavy smog that has hit much of the country's northern regions. Tong Yu / For China Daily

WITHIN THE PAST 10 DAYS, sulfur dioxide levels in the air have exceeded 1,000 micrograms per cubic meter three times in Linfen, North China's Shanxi province, yet the local officials did not issue any warnings. Beijing News comments:

On Jan 4, when almost all major media outlets nationwide reported the high amounts of sulfur dioxide in the smog, a vice-director of the local environmental protection bureau was reported as saying, "Linfen has established a warning system for sulfur dioxide and has been monitoring its density in the air."

However, this time, when being asked about the warning system, the same vice-director responded: "Which city has such a system? Tell me!"

One thing should be made clear: Whether a warning system is needed does not depend on whether other cities have it. That depends solely on whether the pollution is severe enough. On Jan 4, the peak of sulfur dioxide density in Linfen reached 1,303 mg per cubic meter, 60 times that of neighboring cities.

Sulfur dioxide has long been listed as a carcinogen by the World Health Organization, and studies also show that high concentrations of sulfur dioxide in the air result in a higher rate of lung cancer. In 1952, the heavy smog laden with sulfur dioxide that blanketed London is estimated to have been responsible for the deaths of at least 10,000 people.

It seems the local officials of Linfen do not care a bit about the health of local residents. So far, no official has been held answerable for the high density of sulfur dioxide in the air, no apology has been issued by the local government, and no media outlet is allowed to be present at their discussions.

If the Linfen officials insist on not correcting their wrongdoings, the national Ministry of Environmental Protection should do its job. It should punish the local environmental protection officials and further improve the air quality supervision system.