Among all types of pollution, light pollution may be the easiest to remove. Unlike air pollution, water and soil, light pollution does not remain in the environment after the source has been removed, but disappears the moment that the light goes out. Although it is not practical or desirable to remove all artificial light, there is plenty we can do to achieve a more efficient use of light, ensuring that there is light where we need it and not in other places where it hurts.
Blue light (shorter wavelength) is much more harmful than the red light (longer wavelength). This probably is because our evolution over millions of years with the natural changes in the tones of sunrise and sunset. When it starts to get night, the body produces a hormone called melatonin.
Within the above three points, we can highlight the following specific actions
Want to know how much light pollution there in your city? This interactive map provides a breathtaking view of the amount of artificial light emitted in different parts of the world.