Our Bright Cities Are Causing Light Pollution. Should We Be Worried?

58.5 percent population in India are exposed to light pollution. In absence of any law, what does the future hold? 

Published on 5 Oct 2021 5:59 PM on BoomLive

 For two years, Nilesh Desai fought against the use of intense and obtrusive floodlights at Wilson College Gymkhana Club on Marine Drive in Mumbai. He filed multiple complaints with the city administration. His house, he explains, was constantly enveloped in bright lights which remained functional till 4 am. The starry sky and fresh breeze from the sea were muted with thick curtains to block the light. "I refrained my kids from looking outside as the lights could harm their eyes ," Desai says. "We were unable to sleep properly and both my mother and sister-in-law, who was just 40 at that time, had to undergo cataract surgeries." 

The ordeal for Desai and his neighbours ended in 2018 when Mumbai administration ordered the club to remove the floodlights. In absence of any law on light pollution, such victories remain few and far between. The business of lights, meanwhile, is rising exponentially, tinkering with body rhythms, triggering various health disorders and behavioural changes and also impacting wildlife. 

What is light pollution? 

The inappropriate or excessive use of artificial light is known as light pollution and its sources include a building's exterior and interior lighting, advertising, illuminated buildings, stadiums and vehicle headlights. City lights are often blamed for overshadowing the stars at night. Around 83 percent of the world's population lives under skyglow from artificial lights, with 99 per cent people in United States and Europe not experiencing natural night, said a 2016 world atlas of artificial night sky. In India, 58.5 percent population and 24.7 percent area are exposed to light pollution. Is light pollution rising in India? Brightness from outdoor lights increased steadily in India between 1993 and 2013, according to a 2019 study published in the journal Urban Climate. New Delhi, Telangana, Maharashtra, Karnataka and Uttar Pradesh experienced increase in very high light pollution intensity, while West Bengal, Gujarat and Tamil Nadu went from low to high light pollution due to urban expansion, industrial and agricultural development and air pollution in these regions.  Among the cities, Delhi had maximum land area under light pollution, but it was Bengaluru which was mostly intensely lit, researchers found at IIT-Kharagpur, School of Planning and Architecture-Bhopal, and ITM-Gwalior. Bengaluru was followed by Kolkata, Hyderabad, Delhi, and Mumbai in night light intensity. 

How does light pollution impact humans?

Artificial light at night hinders production of Melatonin, a hormone that regulates sleep-wake cycle and also acts as a tumour suppressor. People exposed to artificial lights are thus at a higher risk of low sleep quality, insomnia, depression, besides breast and prostate cancers. Disruption of daily rhythms due to light pollution may also lead to obesity. The harmful impact, however, also varies depending on intensity and wavelength of light. Natural white LEDs, being promoted across the world as energy efficient, are adding to the crisis. An analysis of common types of lamps found that amount of light pollution is highest for lamps with a strong blue light emission, like white LEDs. India has installed over 11 million LED street lights under several government schemes. Light pollution has also been found to increase air pollution. The sky glow that radiates from cities interferes with chemical reactions that naturally clean the air during the night, study done at Colorado University found. 

How does light pollution affect wildlife?

Several nocturnal animals and migratory birds navigate using brighter horizon as a pivot. Light polluted skies are hence confusing them. Hatchlings of Oliver Ridley turtles at Rushikulya beach of Odisha, for instance, would often go astray due to beach lighting. These hatchlings emerge from their nests at night and walk towards brighter horizon because that is the natural direction of the sea. Beach lighting, however, creates an artificial light horizon towards the land and hatchlings spend a lot of energy walking towards it. Many of them die due to dehydration, attacks by predators or energy loss. Artificial lights also attract migratory birds which frequently crash into lampposts or make faulty decision to stop over at a brightly lit, but resource poor location for refuelling. Global studies have also shown negative impact of light pollution on nocturnal pollinators, leading to 13 per cent slump in fruiting and change in foraging habits of animals like mice which keep from well lit areas to avoid predators. 

What can be done to mitigate light pollution? 

Paris forces offices and shops to be dark overnight. In United Kingdom, light emitted from a premise can be treated as an unlawful activity if found to be harmful to health. In US too, several states have implemented regulations for controlling light pollution. Such a policy debate is, however, missing in India. Desai, who made authorities act against Wilson Gymkhana Club, is now raising issue of light pollution from other clubs, under construction buildings, and advertisement billboards. "I have approached so many authorities but they express helplessness to deal with nuisance of artificial light in absence of any clear guidelines or law. I can only seek shelter in Article 21 of the Constitution that provides right to live in a pollution-free environment," said Desai. The only remedy thus remains structural barriers. Shields on street lighting fixture to prevent direct upward dispersal, no over lighting, and diminishing illumination according to time of the night can help reduce light menace. Trees with large canopy sizes can be considered in landscaping to reduce glare. Awareness and advocacy around lighting can also go a longer way as happened in the case of turtles mentioned earlier. 

"Conservation groups have occasionally managed to make some headway in reducing lighting around turtle nesting sites for brief periods. And the state forest department had convinced DRDO to shut off floodlights at its missile testing centre during the nesting season as it is adjacent to the Gahirmatha mass nesting beach. But really, a national policy that can ensure sustained efforts to deal with light pollution is required," said Prof Kartik Shanker, co-author of the study and faculty at the Indian Institute of Science, Bengaluru. Arjun Kamdar, a conservationist who has been studying microfauna and elephants, feels impact of light pollution needs more research. "We have seen how a road cutting through a wildlife sanctuary impacts the movement of animals at night because they tend to avoid oncoming lights from motor vehicles. This disruption can be detrimental to the health of the whole ecosystem, but there are remedial measures available. For instance, a vehicular overpass has been built on Doboka- Lumding road in Lumding reserve forest in Assam. It also has light barriers so that animals can pass under safely without getting scared of vehicle headlights," he said. 

Manu Moudgil is an independent journalist. He tweets at @moudgilmanu

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