The definition of light pollution is the brightening of the night sky caused by street lights and other man-made sources, which has a disruptive effect on natural cycles and inhibits the observation of stars and planets. Light pollution affects animals and people alike: it affects human circadian rhythms, wildlife behavior, and the ability to observe space. An increased amount of light at night lowers melatonin production, which results in fatigue, headaches, sleep deprivation, anxiety, stress and other health problems. This issue doesn’t just stop in the US; it is a world-wide problem, even in places where less artificial lights are used. Some of the most light-polluted countries in the world are Singapore, Qatar, and Kuwait.
There are three kinds of light pollution: glare, clutter, and light trespass. Glare is excessive brightness that can cause visual discomfort. Clutter is a bright, confusing, and excessive grouping of light sources. Light trespass is when light expends into an area where it is not wanted or needed.