Stay inside when the air pollution index reaches very high levels

在空气污染指数极高时留在室内

The results showed that with the main air pollution in China being coal dust, the comprehensive air pollution index of Shenyang was the highest, Dalian the lowest and Zhengzhou in the middle.

结果显示我国大气污染属煤烟型，污染的综合指数以沈阳最高，郑州次之，大连最低。