THE authorities have the right to limit high-emission vehicles like diesel-powered heavy vehicles and gasoline-powered vehicles, whose emissions fail to meet the National II standard, when the air is seriously polluted, according to a contingency plan released by the Shenzhen Municipal Ecology Environment Bureau last week.

The contingency plan grades air pollution into three levels by severity, which are indicated by yellow, orange and red signals. Based on the different signals, three levels of the response system can be initiated.

When the daily average of the air quality index (AQI) reaches 200 for two days, the yellow warning will be issued and a Level III response will be initiated. Children, elderly people and patients with heart diseases and respiratory system diseases are advised to stay indoors. The public and some enterprises are advised to take measures to reduce emissions.

If the AQI reading remains above 200 for more than three days, an orange alert will be issued, compulsory measures will be taken and boilers will suspend the use of diesel, and diesel-powered vehicles and gasoline-powered vehicles whose emissions fail to meet the National II standard will be restricted from roads on respective days according to the odd and even numbers on their license plates.

If the AQI reading remains above 200 for four days, or is forecast to be above 300 for two days or to reach 500, a seriously polluted level, a red alert will be issued and a Level I response will be initiated.

Schools will be closed under such circumstances, major polluting enterprises will suspend production and high-emission vehicles will be restricted from roads, according to the plan.

(Han Ximin)