How do dark sky parks tackle the growing problem of light pollution?

On January 11, 2024, the Pench Tiger Reserve (PTR) in Maharashtra was designated as India’s first International Dark Sky Park, certified by the International Dark-Sky Association. It was the fifth such park in Asia with an aim to protect the night sky and promote astronomy.

So what is a Dark Sky Park and why is it important?

A Dark Sky Park is an area designed around a park or observatory that restricts artificial light pollution. The global night sky has been getting 10 per cent brighter every year over the past decade. This excessive or inappropriate use of outdoor artificial light is affecting human health, wildlife behaviour, and our ability to observe stars and other celestial objects.

One of the major solutions to this growing problem of light pollution is to bring back the dark sky through such Dark Sky Parks. But before looking closely into Dark Sky Parks, let’s first understand light pollution.

This introduction of light into the night is one of the most dramatic changes we have made to the biosphere. Light pollution refers to artificial light that alters the natural patterns of light and dark in ecosystems.

There are several types of light pollution. For example, glare, which is a disruptive light that shines horizontally. Light trespass, which is the unwanted shining of light onto nearby areas. The other important one is sky glow. More than 80 per cent of the world’s population, and 99 per cent of Americans and Europeans, live under sky glow.

A study published in Urban Climate Journal in January 2019 notes that the brightness from outdoor lights has been on a steady rise in various parts of India from 1993-2013. New Delhi, Telangana, Maharashtra, Karnataka and Uttar Pradesh experienced an increase in “very high light pollution intensity” in this period.

Studies have shown that excessive artificial illumination can also cause issues of poor sleep, obesity, diabetes, certain cancers and mood disorders. Light pollution is also impacting animal behaviours, such as migration patterns, hunting and habitat formation in many nocturnal species.

Several organisations are working to reduce light pollution. One of these is the US-based International Dark Sky Association (IDA), formed in 1988 to preserve the natural night sky. IDA educates the public and certifies parks and other places that have worked to reduce their light emissions.

Today, Dark Sky has certified more than 200 places with over 160,000 square kilometres of protected land and night skies in 22 countries on 6 continents.

Apart from the PTR Dark Sky Park, India also hosts its first sky preserve with the Indian Astronomical Observatory (IAO), a high-altitude astronomy station located in Hanle, Ladakh.

The DSP certification for Pench focuses on lighting policy, dark sky-friendly retrofits, outreach, education, and night sky monitoring. It also encourages communities in protected areas worldwide to safeguard dark sites. As cities are growing, more initiatives to preserve the night skies are required to control this growing light pollution.