For three billion years, life on Earth existed in a rhythm of light and dark that was created solely by the illumination of the Sun, Moon and stars. Now, artificial lights overpower the darkness and our cities glow at night, disrupting the natural day-night pattern and shifting the delicate balance of our environment. The negative effects of the loss of this inspirational natural resource might seem intangible. But a growing body of evidence links the brightening night sky directly to measurable negative impacts including

  • Harming human health: Not All Artificial Light have the same impact. Exposure to blue light at night is particularly harmful. Unfortunately, most LEDs used for outdoor lighting, (as well as computer screens, TVs, and other electronic displays) create abundant blue light. To minimize harm from blue light in your home, choose the right light bulb and download a color temperature app that adapts your electronic screen to the time of day. Cool light during the day and warm light at night.


  • Increasing energy consumption. Lighting that emits too much light or shines when and where it’s not needed is wasteful. Wasting energy has huge economic and environmental consequences. Installing quality outdoor lighting could cut energy use by 60–70 percent, save billions of dollars and cut CO2 emissions.


  • Affecting crime and safety. Increased outdoor lighting may make us feel safer, but can you see the guy standing right below the street lamp in the second picture?


  • Disrupting the ecosystem and wildlife. Plants and animals depend on Earth’s daily cycle of light and dark rhythm to govern life-sustaining behaviors such as reproduction, nourishment, sleep and protection from predators. Scientific evidence suggests that artificial light at night has negative and deadly effects on many creatures including amphibians, birds, mammals, insects and plants.


  • Threatening star gazing. Having dark skies alone is now a reason that people travel to destinations as tourists. Most people haven’t seen the Milky Way properly and they don’t know that from truly dark skies it appears bright enough to cast a shadow.Light pollution affects every citizen. Fortunately, concern about light pollution is rising dramatically. A growing number of scientists, homeowners, environmental groups and civic leaders are taking action to restore the natural night. Each of us can implement practical solutions to combat light pollution locally, nationally and internationally.


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Most of us are familiar with air, water, and land pollution, but did you know that light is also a pollutant?

The inappropriate or excessive use of artificial light can have serious environmental consequences for humans, wildlife, and climate. Components of light pollution include:


Skyglow Glare


Light trespass Clutter


Much outdoor lighting used at night is inefficient, overly bright, poorly targeted, improperly shielded, and, sometimes unnecessary. This light, and the electricity used to create it, is being wasted by spilling it into the sky, rather than focusing it on to the objects and areas that need illumination.


If you are working in a city council, you may be here wondering how you could improve your city illumination. Let us give you some help!

6 Tips



Choosing the shape

Shape is very important when choosing a streetlamp. The percentage of light sent to the sky depends on it!



Choosing bulb color

Exposure to blue light at night is particularly harmful, so choosing streetlamps without blue light will be good for people and animals. Here you will find some bulb spectrums. Our favorite? High pressure sodium! It emits mostly all its energy around amber.



High pressure sodium


Fluorescent lamp


Metal halide


Mercury vapor




Night sky images obtained from satellites orbiting the Earth show the effects of excessive lighting. These images are a very useful tool to detect where light should be improved. Besides, the archive of images taken during the last years allow us to study the evolution of the problem.

Milan is losing its amber lights

This image of Milan was acquired after the transition to LED technology in the centre. The illumination levels appear to be similar or even brighter in the centre than the suburbs, and the amount of blue light is now much higher, which suggests a greater impact on the ability to see the stars, human health and the environment.

Milan lights

Belgium vs Germany

Belgium uses mainly orange lighting (low pressure sodium lamps) and illuminates all its highways, The Netherlands illuminates only a few highways. Germany does not light its highways and has much lower illumination levels.

An example of the differences between countries seen from the ISS. Belgium uses mainly orange lighting (low pressure sodium lamps) and illuminates all its highways, The Netherlands illuminates only a few highways. Germany does not light its highways and has much lower illumination levels. Google outreach contributed to the project.

Iberian peninsula

The Iberian peninsula is running out of dark places to star gazing.


World atlas night sky brightness

This is the most recent world atlas night sky brightness. The high scientific quality measures come from campaigns by the UCM around Madrid, of collaboration between the UCM and the FU-Berlin around Berlin (40%) and the Parc Astronomical Montsec and the University Barcelona in Catalonia (40%).