3 min readJun 29, 2026 06:25 AM IST
First published on: Jun 29, 2026 at 06:25 AM IST
Dark nights are becoming increasingly rare. Our cities are dazzled by artificial lights from every direction. The children of our so-called “space age” grow up without ever seeing the Milky Way; the image of a star-studded night has been relegated to digital visuals for occasional wonderment.
So when I recently saw a sign in Dungti, Ladakh, that said, “You are now entering Hanle Dark Sky Reserve: High beams at night strictly prohibited”, I felt a thrill. Ladakh Tourism and the Indian Institute of Astrophysics in Bangalore had organised a unique weeklong festival, and I’d received an invitation to talk about stars before the stargazing sessions in different spots in Ladakh. I’d heard of the Reserve and seized the chance.
The site hosts India’s second-largest optical telescope and an array of detectors for high-energy particles from space. In the middle of the night, I was reminded of the celestial views from my childhood days spent in small villages in Assam.
The right term for what I experienced that night is “noctalgia”. Coined by astronomers Aparna Venkatesan and John Barentine, it describes the sorrow associated with the loss of the night sky due to rising light pollution. What some of us were lucky to see half a century ago is no longer available to most people in India today. This loss is not merely romantic; it has been quantified by astronomers.
A study from 25 years ago revealed that approximately two-thirds of the global population was affected by light pollution. In India, the fraction is comparable to the world average; in the US, the number was as high as 99 per cent. An update on this study was released a decade ago, and it painted a scary picture. The average share of people around the world living in light-polluted environments has risen to 80 per cent.
One might think that being able to see the Milky Way or stars in the night sky is a luxury one can do without. However, artificial illumination impacts our physical well-being. A 2013 study by the American Medical Association found that artificial illumination is wreaking havoc on our circadian rhythms. In darkness, our bodies produce melatonin, a vital hormone that facilitates sleep. But widespread artificial light interferes with this, leading to shorter sleep durations. This heightens stress levels. Doctors have noted that excessive illumination tends to increase blood pressure, making people prone to cardiovascular diseases.
In the animal world, many nocturnal insects use the stars to navigate. Scientists have been studying how urban illumination disrupts the natural navigational abilities of these insects.
It is telling that the Hanle Reserve is a part of the Changthang Wildlife Sanctuary: Preserving natural habitat and dark nights go together. Other states have shown interest in creating similar reserves. What might seem like a small step now is an important move toward protecting our environment.
The writer, visiting professor, IISER Mohali, was an astrophysicist at the Raman Research Institute, Bengaluru
Widespread artificial lighting interferes with melatonin production, leading to shorter sleep durations. This heightens stress levels 
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