Photopollution is not a new phenomenon, it is for the past 50 years, as the country is becoming affluent and urban, there is an increasing demand for outdoor lighting and beyond city limits, thus spreading light pollution in suburban and rural areas.  This form pollution is now prevalent in Asia, Europe and North America, especially in cities such as Los Angeles, New York and Washington DC.  In 2008, National Geographic magazine named Chicago the least polluted city in the United States.

 Some of the main effects of light pollution are –

•  Urban light pollution is a threat to street trees, nature reserves, gardens and garden vegetation.  On the surface there is an unnatural deluge of light on the trees and light pollution causes glare to animals and insects at night.
•  Exposure to intense flood lighting sources can result in permanent photochemical retinal damage in animals as well as humans.
•  Some marine and aquatic organisms including endangered species are also being affected by it.
•  Light pollution and light overloading represent unnecessary greenhouse gas production.

Best ways to prevent light pollution:

• There should be a limit to the external light so that the light is used only where it is needed.  This will result in energy savings, lower operating costs and more efficient use of light, due to better night visibility, night will look better, sky visibility, less glare, better safety, and a more attractive environment.
•  Properly designed full cutoff lighting reduces operating costs, saves energy and prevents light pollution.
•  The range of lighting must be determined, installed and operated by:
•  control of light.
•  Blocking out excessive light.
•  Minimize direct upward emissions.
•  Promote effective security.

Photo from:http://www.askaboutireland.ie/enfo/irelands-environment/noise/light/