In short
- Light that leaves the site or goes up into the sky is wasted, intrusive and harmful to wildlife.
- Four tools control it: shield, aim down, choose warm colour and switch off late at night.
- Near Odisha’s nesting beaches, light reaching the beach can disorient sea turtle hatchlings. Coastal projects need beach-facing lighting designed with this in mind.
Three kinds of obtrusive light
- Sky glow: light directed or reflected upwards, brightening the night sky over towns and resorts.
- Light trespass: light falling where it is not wanted, such as a neighbour’s bedroom window or a beach.
- Glare: bright, unshielded sources visible from roads, neighbours and the beach.
All three come from the same causes: unshielded fittings, upward aiming, excessive output and lights left on all night.
Shield and aim
- Full cut-off or fully shielded fittings emit no light above the horizontal. Use them for paths, car parks and general area lighting.
- Aim at surfaces, not past them. An uplight on a facade should stop at the parapet; downward grazing from the top keeps light on the building. See Facade Grazing.
- Light trees into the canopy, not beyond it into open sky. See Uplighting Trees.
- Low-level path lighting (bollards, step lights) keeps light near the ground.
Choose warm, use less
- Warmer light (2700–3000 K or lower) contains less blue, which scatters more in the atmosphere and affects many species more strongly.
- Light only to the level needed. In dark surroundings, contrast does the work; low levels are enough. See The Night Image.
Switch off
- An astronomical clock with an evening scene and a late-night curfew scene.
- Decorative facade and landscape layers off after a set hour; path and security light remain, ideally on presence sensors.
- Festival scenes are temporary and should revert automatically.
The Odisha coast and sea turtles
Odisha’s coast includes globally important nesting beaches for olive ridley sea turtles, including the Gahirmatha coast, the Rushikulya river mouth and the Devi river mouth.
- Hatchlings emerge at night and find the sea by moving towards the brightest horizon, which is naturally over the water.
- Artificial light from buildings, roads and resorts behind the beach can draw them inland, where they die from exhaustion, predators or traffic.
- Nesting females may also avoid brightly lit beaches.
For projects near the coast:
- No light should fall directly on the beach or be visible from it during the nesting and hatching season.
- Use fully shielded, low-mounted, warm or amber fittings on beach-facing sides.
- Screen views of interior light towards the beach with planting, walls or blinds.
- Switch off decorative and beach-facing lighting at night during the season.
- Check current requirements with the Odisha Forest Department and the applicable coastal regulations before design, as protected areas and seasonal rules apply.
Neighbours and the street
- Check spill onto adjacent plots and windows.
- Avoid bright sources visible from roads; glare reduces drivers’ vision.
- Security lighting should be sensor-controlled and shielded, not floodlights left on all night.
Specification notes
- Use fully shielded fittings for paths and area lighting; no upward light from area fittings.
- Aim facade and tree lighting so light stops at the surface.
- Default to 2700–3000 K or warmer; amber near nesting beaches.
- Provide evening and late-night scenes on an astronomical clock; sensor-controlled security light.
- For coastal sites, keep light off the beach and screen beach-facing views; consult the Forest Department.
Frequently asked questions
What is dark sky friendly lighting?
Lighting that is shielded to prevent upward light, aimed only where needed, warm in colour, at the minimum level necessary, and switched off when not needed.
How does artificial light affect sea turtles?
Hatchlings use the brightest horizon to find the sea. Artificial light behind the beach can lead them inland. Lights visible from nesting beaches should be shielded, dimmed or switched off during the season.
Do warm lights reduce light pollution?
Warmer light contains less blue, which scatters more in the sky and affects many animals more. Shielding and reducing output matter even more.
Continue the series
About the author
Prem Rout, Founder of JMAP Solutions, set up in 2022 to deliver lighting, automation and building management solutions from Bhubaneswar. Over 15 years of experience in building products, construction and project business development across Mumbai and Odisha, working where design intent meets specification and site delivery. Connect on LinkedIn.
