Count. Billboard lights are on at night, which belongs to light pollution. According to the Law on the Prevention and Control of Urban Environmental Noise Pollution, it is known that the night is from 22: 00 at night to 6: 00 the next morning, during which light pollution is regarded as a nuisance. Light pollution is a kind of environmental pollution phenomenon, including visual interference and discomfort caused by reflection, scattering and radiation, and social problems caused by it. Therefore, night lighting of billboards is a hassle.