Never has Beijing had such a severe contingency plan for serious air pollution. But it is a must.

The plan, which was preliminarily adopted by the municipal government over the weekend, defines the severity of air pollution by four levels. It stipulates that if smog is expected to be severe for three consecutive days, motor vehicles will be banned according to whether their license plates have last number odd or even. In that way, the number of cars on the road will be reduced by half.

In addition, primary schools and kindergartens will close; some plants will suspend production or reduce their emission of pollutants by 30 percent; and open-air barbecues and some construction projects will also be required to stop work. Eighty percent of government cars will be prohibited from running on those days.

It is obvious that air pollution has become a scourge that increasingly compromises the livability of the capital city and thus prevents it from becoming an attractive international metropolis.

Necessary as the emergency plan is, it is sad that a national capital must take measures that compromise the quality of life and convenience of residents solely because of air pollution.

Although the municipal government has promised to invest 200 billion yuan ($32.8 billion) to 300 billion yuan in the next five years to improve air quality, it is imperative that it also reflects on its urban development plan, which aims to develop the capital city into the center of almost everything.

If the city continues to expand, it will definitely have even more motor vehicles and be more densely populated, which will make it increasingly difficult to disperse smog.

The State Council released its action plan for air pollution control, requiring that the area of Beijing and Tianjin municipalities and Hebei province reduce PM2.5 emissions by 25 percent in five years.

There may be some room for the capital city to improve its air quality. It could reduce exhaust emissions from motor vehicles and the use of coal by raising the standards of exhaust emissions and pollutant emissions from industrial enterprises. But these should be on the premise that the city won't expand.