A nominated body of the Engineering Council. All Living things adjust their behaviour according to natural light. Man's artificial light has done much to safeguard and enhance our night-time environment but, if not properly controlled, obtrusive light can present serious physiological and ecological problems. Light pollution , whether it keeps you awake through a bedroom window or impedes your view of the night sky, is a form of pollution and without too much trouble can be substantially reduced with out detriment to the lighting task in both urban and rural areas.
Sky glow is one form of light pollution.
Glare , the uncomfortable brightness of a light source when viewed against a dark background, and light trespass , the spilling of light beyond the boundary of the property on which the source is located, are other forms of light pollution. These waste not just electricity and thereby large sums of money, but more importantly the Earth's finite energy resources, which in many cases results in unnecessary emissions of greenhouse gases which should be kept to a minimum. Direct light downwards wherever possible to illuminate its target, not upwards. If there is no alternative to up-lighting, then the use of shields and baffles will help reduce spill light to a minimum. It is a cause of light pollution and a waste of money.