pollution. According to the information of official website in Pingshan BYD Factory, it is known that it is mainly the factories that make vehicle parts. As of April 3, 223, the air pollution index is 46mg/m3, and the allowable air emission index issued by the People's Republic of China is 4mg/m3, so it is air pollution. Air pollution is a phenomenon that some substances enter the atmosphere due to human activities or natural processes, showing sufficient concentration for enough time, and thus endangering human comfort, health and welfare or the environment.