Property patrol car tweeter is illegal. What law?

People's Republic of China (PRC) Environmental Noise Pollution Prevention Act

The state has divided the sound zones, and sanatoriums and other places belong to category 0 sound environment functional zones, which cannot exceed 50 decibels during the day and 40 decibels at night; Ordinary residential buildings belong to 1 class acoustic environment functional area, which cannot exceed 55 decibels during the day and 45 decibels at night. Therefore, if the decibel around the sanatorium exceeds 50 decibels during the day, it is noise. You can complain that it disturbs people. If the decibel of an ordinary house exceeds 55 decibels during the day, it is noise and you can complain.

According to the relevant laws and regulations, it is forbidden to use loudspeakers in business activities or attract customers by other methods that emit high noise, and it is forbidden for any unit or individual to use loudspeakers in areas where noise-sensitive structures is concentrated in urban areas. Anyone who violates the provisions of this law shall be given a warning by the public security organ and may also be fined. If environmental noise pollution is caused, the public security organ shall order it to make corrections and may also impose a fine. If the people's government at or above the provincial level decides according to law that the competent administrative department of environmental protection of the local people's government at or above the county level shall exercise the power of administrative punishment prescribed in the preceding paragraph, it shall make a decision.