What does the weather forecast mean by 36 1 serious?

The air quality index is 36 1, which is seriously polluted.

According to Baidu Encyclopedia, 36 1 is a serious weather forecast, which means that the air quality index is 36 1, which belongs to six levels of serious pollution and is very harmful to human health.

Air pollution usually refers to the phenomenon that some substances enter the atmosphere due to human activities or natural processes, and show sufficient concentration in sufficient time, thus endangering human comfort, health and welfare or the environment.