Denmark recently drew global attention by switching to red streetlights in selected areas, especially near ecologically sensitive zones and low-traffic stretches. The reason was not aesthetic. It was ecological and safety-oriented, aiming to reduce light pollution and lessen harm to wildlife while keeping roads safe for humans. For cities around the world grappling with the effects of rapid growth on both people and nature, this experiment raises an important question, can something as simple as the colour of street lighting help save lives?
In India, where urban expansion increasingly overlaps with natural habitats, this question is especially relevant.
Most conventional streetlights emit bright white or bluish light. While effective for human visibility, such light scatters widely, changes the night environment, and disrupts the natural behaviour of animals. Many species rely on low-light conditions to navigate, forage, or avoid danger. Bright light can disorient animals, slowing their reactions or pushing them toward roads where they face collisions.
Red light behaves differently. Its longer wavelengths scatter less and interfere minimally with animal vision. Studies and practical trials suggest that red lighting can help preserve natural night patterns and reduce disorientation among nocturnal wildlife. In Denmark, red streetlights were installed in areas where unfiltered white light could harm migratory birds and other species, while still maintaining road visibility for humans.
India’s road network is among the busiest and most extensive in the world, and this comes at a human cost. In 2022, India recorded about 1.73 lakh deaths from road accidents, with more than 4.6 lakh crashes across the country. These figures include pedestrian, two-wheeler, and vehicle fatalities, highlighting that road safety remains a major public health challenge.
These numbers are driven by systemic issues, such as speeding, mixed traffic, limited separation between fast and slow vehicles, and poor enforcement, problems that red lights alone cannot fix. But there is also an ecological component that is often overlooked.
Roads increasingly cut through wildlife habitats. A study in Assam’s Kaziranga-Karbi Anglong region found thousands of wildlife deaths along a single 64-kilometre stretch of highway, where vehicular collisions claimed the lives of more than 6,000 animals from over 50 species in a single year. Similarly, surveys in Tamil Nadu’s Western Ghats recorded nearly 5,500 animal deaths along a 50-kilometre road segment over one year, affecting at least 72 species.
Smaller, localised data also paint a stark picture. In the Hosur forest range near the Chennai-Bengaluru highway, 34 wild animals, including deer and an elephant, were killed in collisions over five years, mainly at night. In the fiscal year 2024-25, reported animal deaths from road incidents rose from 508 to 582, showing that conflict increases as roads and traffic volumes grow.
In theory, red streetlights could help on specific stretches of highways that intersect wildlife corridors. By reducing the disorienting effects of bright white light, they might allow animals to move more naturally and lower collisions. For drivers, red lighting could still provide enough visibility to spot movement and navigate roads safely.
However, the Indian landscape presents challenges. Traffic is varied, with mixed vehicle types, pedestrians, and frequent roadside activity. In such conditions, lighting must prioritise human safety without harming ecological sensitivity. Red light alone cannot resolve deeper issues like speeding, insufficient signage, sharp bends near forests, or lack of underpasses and fencing for animal crossings.
Red streetlights should not be seen as a cure-all. India needs a multi-layered strategy that combines improved lighting with structural measures, such as dedicated wildlife crossings, speed controls in animal-prone zones, clear signage, and technology-aided alerts for drivers. Lighting should be used selectively in areas where ecological conservation and road safety overlap.
Denmark’s experiment shows that small urban design choices can make a difference when guided by science and sensitivity to both human and non-human needs. For India, where cities and forests meet in a complex mosaic, this means planning roads and lighting systems that recognise the rights of all who use them. The goal should be coexistence, not collision.
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