Light Pollution

Light Pollution | Why Darkness is Important For The Earth?

Darkness is a dream for urban people. Globally, nights are becoming brighter due to urbanization. Wherever our eyes reach, we see different types of light: street lights, security floodlights, ornamental lights, etc. All these contribute to global light pollution.

Before we move further I will tell you a real story, a sad story;

On a clear night in 1994, Los Angeles faced an earthquake and just before dawn, the entire city was out of power. Some residents who had stumbled outside called various emergency centers and a local observatory to report a mysterious cloud in the sky.

That mysterious cloud in the sky turned out to be the band of the Milky Way, our home galaxy which had long been wrapped by the city’s light.

Isn’t it a sad thing for humans?

When is the last time you have enjoyed the milky way?

Has humans’ great invention become a curse for the earth?

The light bulb is the most transformative invention that man has given to the planet. At the push of a button, darkness turns into light and night turns into day. Which allows us to do things like playing games for a long night or roam in the city streets freely at night.

These glittering lights have stolen the darkness from us. It is harming our ecosystem whose lifecycle depends upon the dark.

What is Light Pollution?

Everyone is aware of air pollution, water pollution, and soil pollution but did you hear about light pollution?

Yes, light is also a pollutant.

The usage of unwanted, inappropriate, excessive artificial light causes Light Pollution. It can seriously affect the environment, humans, wildlife, and climate.

As per the study published in the Journal, Urban Climate, brightness from outdoor lights increased steadily between 1993 and 2013. Telangana, New Delhi, Maharastra, Karnataka, and Uttar Pradesh all experienced increase in light pollution which brought about a massive change in the climate.

According to the researchers, satellite data shows that the earth’s artificially lit outdoor surface at night grew by 2 percent annually, in brightness from 2012 to 2016. Every year earth is getting brighter than earlier years.

How light pollutes the environment?
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Types of Light Pollution

  • Glare: Visual discomfort because of excessive light
  • Skyglow: The skyglow is an omnipresent sheet of light across the night sky in and around the cities that can block all the brightest stars from view
  • Light Trespass: Light falling where it is not required or intended
  • Light Clutter: It is the excess grouping of lights that creates confusion, which can be cause for an accident. It may be due to bad street light design, advertisements surround the roadways etc.

You can check the pollution level of your city by using NASA Blue Marble Navigator.

NASA Blue Marble Navigator
NASA Blue Marble Navigator

Effects of Light Pollution

A recent study has shown that the skyglow forces dung beetles in the city to abandon the Milkyway as their compass and rely on earthbound artificial lights as beacons.

Dung beetles use the Milkyway to orient themselves. They use the stripe of light in the sky as a reference point to move in a straight line. They are the only species in the animal kingdom to do so.

God created everything with a purpose. Life on earth survived with lights and darkness. All that is created by the illumination of the sun, moon, and stars. Now the day-night pattern is disrupted by the artificial light which overpowers and harms the delicate balance of the environment.


1. Ecological Consequences of light pollution

Artificial lights disrupt the whole ecosystem. Generally, Nocturnal animals sleep in the morning and are active at the night. Their nighttime environment is totally changed due to Light Pollution. Their night turned into day because of artificial lights.

The glare that comes from artificial light also impacts wetland habitats like frogs and toads. Their nighttime croaking is a part of breeding routines. Artificial lights disturb nocturnal activity, reproduction and reducing their population.

2. Artificial lights impact the hatchling process of Baby Sea Turtles

Sea Turtles hatch during the night at the beach. Hatchlings find the sea by looking at the bright horizon over the ocean. Artificial lights divert their way from the ocean. Causing millions of hatchlings to die every year.

Dr. APJ Abdul Kalam had taken a step to save hatchlings Olive Ridley Sea Turtles when he was the director of DRDO.

He directed to stop all the missile testing and other major activities during the hatchling season of turtles to save them. He also ensured all the floodlights are switched off in Wheeler Island. Gahirimatha Beach which is located near Abdul Kalam Island, in Odisha’s Kendrapada district. Gahirimatha Beach is the world’s largest site for turtles today.

Sea Turtle

But, in 1999 after Dr. Kalam’s departure, the officials failed to keep up the words of Dr. APJ Abdul Kalam and tested missiles from Wheeler Island.

3. Effect of Artificial Light on Bird species

Many bird species, small insect eaters, generally migrate at night. Migrating birds and nocturnal birds use the light of the moon, star, and setting sun to navigate their bi-annual migrations. Light pollution hides all their navigation tools

Every year millions of birds collide with illuminated buildings and towers & die.

Migratory birds need a seasonal schedule to fulfill their purpose. Artificial lights makes it difficult for them to reach their destination. They miss their ideal conditions for nesting, foraging, and other behaviors.

Bird Species are affected due to artificial lights

4. Artificial Light is a new threat to pollination

Pollinators play a very essential role in wild plants and producing crops. Their numbers are declining worldwide and this can be a new threat. The decline is due to habitat changes, intensive agriculture, excessive use of pesticides, spread of pathogens, invasive alien species, and climate changes.

These artificial lights at night affect nocturnal pollination and it may impact the plant reproductive system. Research shows that there is a 62% reduction in pollination, between artificial lit places as compared to a dark area. This resulted in a 13% reduction in fruit plants though it received numerous visits by diurnal pollinators.

This demonstrated that artificial lights at night are a threat to pollination.

Impact of Artificial Light on Human

Humans need to understand the rhythm of the natural day and night cycle. We evolved with this cycle. But, due to the vast increase in artificial lights, we are not experiencing true darkness.

  • Artificial light at night can increase the risk of obesity, depression, sleep disorders, diabetes, etc.
  • Circadian Rhythm: It disturbs our circadian rhythm or sleep-wake pattern due to artificial light.
  • Suppresses melatonin production: When bodily circadian rhythm disturbs it decreases the melatonin production. Melatonin keeps us healthy. Its anti-oxidant properties provide better sleep, increases the immune system and lowers cholesterol levels.
  • The risk of breast cancer in women may increase as a result of being exposed to artificial light at night and working in night shift.

Causes of increasing Light Pollution

1. Poor Planning

Improper placement of street lights, signage can create glare, light trespass, and light clutter.

2. Unnecessary Uses

The unnecessary use of light at home switching on all the lights at home during evening/ night time, excessive usage of light during the festive season, or important occasion increase the risk of light pollution.

3. Overpopulation

Many businesses or residents gathered in one place causes light pollution.

4. Smog and clouds

The environment looks brighter because of smog and clouds as they reflect light emitted by the cities.

5. Vehicle Lights

Lights of motorcycles and cars cause light pollution, especially at night time. Without other light sources also, these areas shine so brightly. High beams or fancy lights on automobiles can cause pollution at night.

6. Street Lights

Unplanned street lights near residential areas can affect human sleep.

7. Night-time Lights

All illuminated advertising lights and nighttime lights in residential areas can affect adversely.

8. Downtown Area

The downtown areas like skyscrapers, commercial places are quite illuminated. They emit lights almost 24×7 to attract traffic for commercial purposes. This contributes too light pollution.

Downtown Cities

Solutions to Light Pollution

The basic approach to solving this issue is Planning and education.

Street lights and any other lights should be placed with proper planning wherever needed.

Most important is to educate people on the value of electricity and how it harms human beings. The effect can be

1. Light Shields

Light shields are helpful to prevent lights from spreading and concentrate on one place. It solves the problem of light pollution and its negative impacts on nearby houses and inhabitants.

Street Light Shield

2. Warm Lights

Cold short-wavelength lights can impair night vision. Warm lights can help to prevent them to a certain amount and help to solve light pollution.

3. Certified Lighting

Certified light reduces glare, skyglow, and light spill. The impact of these lights is lesser on the environment.

4. Motion Sensors

Motion sensors are a great way to stop light pollution. As it ensures the light is turned on when the motion sensor is triggered. It saves a lot of electricity thereby reduces light pollution.

5. Cut-off Lights

Cut-off Lights
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Cut-off lights don’t affect the surroundings and nearby houses as the lights are spread in a determined spot. Full cutoff lights are best to reduce light pollution.

6. Turn off the light when not needed

As more people will understand the importance of turning off the light when not required, it will conserve energy and reduce light pollution.

This is the most effective and easiest way to prevent the effect of light pollution.

Our whole environmental system will be benefitted at night time just by switching off the light. Also, it will be helpful to slow down global warming.

These are some solutions we can adopt and implement in our daily routine. Yes, I can understand it is difficult to change the habits of people and will be expensive if we redesign everything.

However, by taking one step at a time we can bring about a drastic change in our environment. slowly we can change our habits and educate more people on environmental issues.

Write me with your opinions in the comment section on how we can reduce light pollution together we can change the world ? What are the steps you are following now?

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