How Excessive LED Street Light Pollution Could Impact you and the Environment

New generation LED lighting, now a must-have for street lighting, can do more harm than the good if not implemented in moderation, warn experts. In fact institutions and the public at large seem to be indifferent to LED light pollution which is spreading in diverse ways impact health and environment.

If at all a wakeup call was needed, this is it!

Excessive use of LED street lighting could cause serious damage to the health of human beings, warned lighting designer and educator Mr. Anil Valia, speaking in Hyderabad recently.

Prolonged exposure to blue light, which is also emitted by LED TVs, computer and mobile phone screens and is 35% of the light LED sources emit and is 10% more than in CFL lighting, will lead to eye strain, and vision problems, the expert warned. The whiter the LED, the higher the blue light proportion, he cautioned.

Blue light affects the back of the eye, and precipitates age-related macular degeneration, which causes irreversible vision damage. Ringing a caution bell, Mr. Valia said. Chronic exposure to blue light at night could further interfere with the circadian rhythm (body clock) by lowering the production of Melatonin, the hormone that regulates sleep.

Almost 35% of the light emitted by LED light sources is blue light compared to 25% in CFL bulbs making the excessive use of the former hazardous to to human health

Coming at a time when most states and the Central government are on an overdrive to light up streets across the country, and in fact the night skies, with solid-state LED street lights that emit milky-white light, which at times appears brighter than day light, the word of caution and call for moderation in use of such lighting by Mr. Valia, who is a world renowned expert on LED lighting, is indeed worth noting.

World’s Largest LED Project

Hyderabad is well on its way to becoming the most LED-lit city in the country if not in the world, with the 4.5 lakh lights slated to be retrofitted in what is apparently the world’s largest such project being undertaken by the GHMC. The Rs 270-crore project will be implemented by Energy Efficiency Services Ltd (EESL), a joint venture of four public sector power companies, with no upfront cost to GHMC, reported the Hindu Business Line some time back. The  World’s largest LED street lighting project retrofitting 4.5 lakh poles across Hyderabad

All the conventional street lights will be replaced with energy efficient LED street lights under this project, as per the G.O.No.194 and the agreement with EESL  The municipal Corporation will pay back EESL for the project cost through deemed savings mode, over a period of seven years.

The GHMC is implementing reportedly the World’s largest LED street lighting project retrofitting 4.5 lakh poles across Hyderabad

While it is a fact that LED lighting is cheaper, more energy efficient and delivers higher luminance than conventional lamps, Mr. Valia pointed out to studies by the American Medical Association (AMA) that showed the medical hazards to humans from it. The AMA study said the increasing popularity of LED lighting is also raising new questions and reviving older concerns about unwanted impact of these light sources such as light pollution, discomfort glare, circadian disruption and retinal damage via blue light. (A counter study by the US-based Lighting Research Center (LRC), which seeks to increase the usage of lighting systems,  sought to debunk the AMA study downplaying the state hazards by the medical body.)

However, according to Christopher Kyba of the GFZ German Research Centre for Geoscience who studied the light density across the globe spread over a few years, the “energy saving” effects of outdoor LED lighting for country-level energy budgets could be smaller than might be expected from the increase in luminous efficacy compared to older lamps.

Even as the debate rages on the pros versus cons of LED lighting, which has transformed lives and livelihoods in many cases corelated to increases in national GDP growth rates, there is however a case for regulation and moderation in installing them, the same as indoor LED lighting is necessary, experts warn.

Guidance for lighting of public streets, roads, and highways in India is provided in the Indian Standard (BIS, 1981). However, since these guidelines are not enforced by any regulatory authority, it is common for municipalities to be unaware of the standards, and many fail to comply, pointed out a study commissioned by the Bureau of Energy Efficiency, Ministry of Power. The most common reasons for inefficient street lighting systems in municipalities are:

• Selection of inefficient luminaires


• Poor design and installation


• Poor power quality


• Poor operation and maintenance practices

Street lighting can account for 10–38% of the total energy bill in typical cities worldwide, the study notes going on to prescribe guidelines for implementing street lighting projects in the country.

Street lighting can account for 10–38% of the total energy bill in typical cities worldwide

Light Pollution

A phenomenon that has been discussed little the world over, and particularly in India, is that of light pollution which has been a growing problem for decades.

The Lighting Research Center maintains that light pollution is an unwanted consequence of outdoor lighting and includes such effects as sky glow, light trespass, and glare.

Sky glow is a brightening of the sky caused by both natural and human-made factors. The key factor of sky glow that contributes to light pollution is outdoor lighting.

Light pollution is an unwanted consequence of outdoor lighting and includes such effects as sky glow, light trespass, and glare.

Light trespass is light being cast where it is not wanted or needed, such as light from a streetlight or a floodlight that illuminates a neighbor’s bedroom at night making it difficult to sleep. Glare is objectionable brightness that can be disabling or discomforting. There are several kinds of glare, the worst of which is disability glare, because it causes a loss of visibility from stray light being scattered within the eye. Discomfort glare is the sensation of annoyance or even pain induced by overly bright sources.

The recent introduction of LED bulbs and lighting systems has increased the amount of light coming from cities by a considerable amount, according to Christopher Kyba who studied light density across the globe spread over a few years. The amount of artificial light coming from Earth’s surface at night has increased in radiance and extent by two percent every year for the past four years—driven by the rapid adoption of bright LEDs and development, the study reveals.

“The amount of artificial light coming from Earth’s surface at night has increased in radiance and extent by two percent every year for the past four years—driven by the rapid adoption of bright LEDs and development.”

[caption id="attachment_684" align="aligncenter" width="816"] The night skies in India have got brighter since 2014 making viewing stars almost invisible. Source[/caption]

Environmental Hazards

Apart from human health hazards, light pollution, particularly the blue light emitted by LED bulbs, doesn’t just make it hard to stargaze but can also causes serious consequences for wildlife, whose biological rhythms and nocturnal instincts are disrupted when they are near a lot of artificial light. In some cases, it can even make spring arrive early.

The more environmentally alive communities and LED lighting experts are thus recommending moderation in LED lighting pointing to a clear consensus among scientists that colour temperature affects the circadian rhythm in both plants and people and affects melatonin production in people. Excessive and poorly directed night lighting inhibits wildlife mating, migrating, navigating, and feeding. For instance, fireflies require dark skies for mating.

In fact some studies note that while it is certain that in the near term artificial light emission into the environment will continue to increase, further eroding Earth’s remaining land area that experiences natural day-night light cycles, it is proven that artificial light is an environmental pollutant and threatens 30% of vertebrates and more than 60% of invertebrates that are nocturnal, apart from effecting plants and microorganisms.

Therefore, some communities and civic authorities are implementing LED lighting only when there is a proven benefit in terms of human safety and reduction in crime rates. In other instances, they are even resorting to automated switch-on, switch-off mechanisms while limiting all LED lighting (including signage) to 3000 Kelvin or lower as recommended by the BIS and other bodies.

While some studies and demonstration projects in fact show that prosperity, safety, and security can be achieved with conservative light use, experts are suggesting that lighting can be reduced or turned off late at night without compromising safety in the moderately lit places to reduce artificial light emissions.