Blinded by the light pollution: Cities seek to restore night

Published 7 June 2026 · india

Artificial lights are blotting out the moon and stars, harming human health, and disrupting the natural world. Why is this a problem? And how can

Artificial lights are blotting out the moon and stars, harming human health, and disrupting the natural world. Why is this a problem? And how can we stop it without sitting in the dark? A streetlight right out in front of your house can make it easier to safely get in the door at night — but good luck trying to sleep without heavy curtains. That's just one example of how artificial light is useful in many aspects of our daily lives, as well as a major problem. Our world is illuminated by more artificial light than ever before. A recent US study found that artificial light emissions at night increased by about 16% globally from 2014 through 2022, according to research published in Nature. Areas experiencing increased brightening also saw the intensity of the light increase, by an average of 9%. Nights are brighter than ever — especially in fast-growing regions of China and India Image: Michala Garrison/NASA Earth Observatory Too much artificial light can make us sick We can switch off light sources such as computers, phones, TVs and lamps ourselves. But other sources are beyond our control: streetlights, headlights on cars, illuminated monuments, flashing billboards, and spotlights on construction sites, storefronts, bus stops, parking lots, sports fields and stadiums, to name just a few. Being exposed to artificial light to such an extent can disrupt our natural sleep-wake cycle, destabilizing our hormonal balance and increasing the risk of metabolic disorders such as diabetes, depression and obesity. The color of light also has an effect. The colder, or whiter, the light, the more it resembles daylight — and the more it suppresses the hormone melatonin, which is what makes us feel sleepy in the evening. No other environmental condition has remained unchanged over the millennia like the natural light of the sun, moon and stars. All living things have adapted to this rhythm.

More than half of all species are nocturnal — if the nights become brighter, it could have devastating consequences. Insects are attracted to artifical light at night; billions are killed each year Image: David McNew/Getty Images Migratory birds use the moon and stars to navigate. Artificial light can distract and divert them from their routes, leading to detours and exhaustion. Other birds can be tricked into laying their eggs too early in the season, when there aren't enough insects for newly hatched chicks to eat. Insects such as moths and beetles use the light from the starry night sky to find food and mating partners. But artificial lights are much brighter and inevitably draw them away. They continuously circle the light source until they drop to the ground, dead with exhaustion. Billions are killed in this way each year, a devastating toll when insects are already threatened by pollution, declining biodiversity and other dangers. Nocturnal mammals such as hedgehogs and bats generally avoid well-lit places; in our brighter world, their habitat is steadily shrinking. And light can create an artificial barrier that some fish species will not cross. Lights cast on the surface of the water from an overarching bridge, for example, can prevent eels from swimming by — a major problem during their migratory spawning period. The world is too bright To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Brightest night skies in China, India The Nature study found that the increase in nighttime light emissions since 2014 was highest in Asia, particularly in the economically growing regions of China and India. In the United States, light pollution increased most on the West Coast because of the growing economy and population in California's cities. The East Coast, and parts of the US Midwest, by contrast, have become darker — in part because of a shrinking industrial sector, fewer residents and more energy-efficient lighting.