In Gladsaxe, authorities have replaced white streetlights with red LEDs to reduce light pollution and protect nocturnal wildlife, especially bats that are sensitive to short-wavelength light. Studies show red-spectrum lighting interferes far less with bat navigation and feeding, while still keeping roads safe and energy use low. The project, part of a wider sustainability effort, shows how urban infrastructure can balance visibility, climate goals, and biodiversity by rethinking something as simple as street lighting.

Denmark Just Switched to Red Streetlights, Solving a Problem Every Modern City Deals With