Light pollution is the emission of artificial light into areas where it is unneeded or unwanted.
Any fixture that shines all or a portion of its light to the sides rather than toward the ground pollutes the sky, or perhaps a neighboring yard or window, with excess light. Many other environmental, social, and economic problems are associated with light pollution. Light pollution is a worldwide problem which affects almost the entire human population. While society has realized the harmful effects of air pollution, water contamination, and indiscriminate use of natural resources, light pollution continues unbeknownst to mankind, insidiously destroying our natural environment. This seemingly simple problem creates a multitude of side-effects which are responsible for washing out the splendor of the night sky, robbing this and future generations of our natural heritage.