Final answer:
Operating buses with interior lights on during daylight hours is forbidden to prevent light pollution and its negative effects on the environment and human health.
Step-by-step explanation:
Operating during daylight hours with bus interior lights on is forbidden in order to avoid light pollution. Light pollution refers to the excessive and unnecessary artificial light that is emitted and scattered into the atmosphere, causing negative effects on the environment, wildlife, and human health. When bus interior lights are turned on during daytime, they contribute to the overall light pollution and hinder the visibility of stars and planets in the night sky.