Artificial Light at Night Impacting Nocturnal Species: A Dimension of Light Pollution

In the glimmer of urban skylines and the celebration of 24/7 economies, we often overlook a growing environmental threat that is not ingested or inhaled, but rather perceived visually. Light pollution, the unchecked spread of artificial light at night (ALAN), has emerged as a significant disruptor of nocturnal ecosystems across India and the globe. It is no longer just a matter of aesthetic or energy waste, it is an ecological crisis. On 23-12-2024, the National Green Tribunal took suo motu cognizance of the death of seven flamingos near Delhi Public School (DPS) lake in Navi Mumbai. The Tribunal noted that:

3. … death of the flamingos can be attributed to a scientific phenomenon called “light pollution”, which partially impairs the vision of the birds due to their fragile eyes … the newly installed light-emitting diode (LED) lights disorient and misguide the birds while flying, which then happen to crash with random objects and get injured.¹

This incident brought to light a growing but insufficiently addressed environmental concern in India: the harmful impact of artificial lighting on wildlife, especially species that rely on darkness for survival. These artificial lights impaired the birds fragile vision, causing them to crash into surrounding structures. This event, while tragic, is symbolic of a broader pattern one where wildlife is increasingly being pushed out of its natural rhythms due to the glow of human progress.

Beyond infrastructure and urban growth, light pollution has its roots in social and cultural behaviours that unintentionally contribute to environmental degradation. Festivals like Diwali, Eid, Christmas and Navratri, while spiritually and socially significant, frequently cause seasonal increases in night-time brightness. According to a global study conducted by Francisco Ramirez et al. (2023), such cultural festivals considerably contribute to global light pollution spikes, affecting annual illumination patterns well after the festive season.² In India, where socio-religious festivities are common and emotionally charged, the junction of cultural traditions and ecological concern is underserved. Urban illumination during festivals, particularly in metropolitan and Tier II cities, causes prolonged exposure to ALAN, which has a direct impact on wildlife. Moreover, unregulated lighting in urban gardens, monuments, highways, and housing colonies has become normalised, often without consideration for its environmental footprint.

Light pollution and nocturnal biodiversity disruption

ALAN fundamentally alters the natural day-night cycles that nocturnal and migratory species rely on. Its presence can suppress melatonin, disturb hormonal cycles and trigger disorientation, ultimately altering behaviours critical for survival such as reproduction, migration and predation. A study by Carolyn S. Burt and Jeffrey F. Kelly (2023) highlights how ALAN acts both as an attractant and a repellent for migratory species, disrupting phenology and triggering cascading ecological shifts.³ The American Bird Conservancy estimates that over one million migratory birds die annually in the US due to collisions linked to city lighting a trend increasingly echoed in India’s urban corridors.⁴ Likewise, in Indian coastal States like Goa and Odisha, mass disorientation of olive ridley sea turtle hatchlings has been observed, with artificial beachfront lighting drawing hatchlings away from the sea a behaviour noted in studies conducted by the Wildlife Institute of India.⁵ Similarly, bats, moths, frogs, and migratory birds experience reduced foraging efficiency and altered predator-prey dynamics due to the interruption of darkness. Delhi and Mumbai, with their dense networks of high-intensity lights, present especially dangerous flyways for birds. In a 2019 satellite study by Mongabay India, substantial increases in artificial lighting across States like Delhi, Maharashtra and Uttar Pradesh were noted between 1993 and 2013.⁶ The increasing brightness has fragmented dark habitats and narrowed the ecological buffer zones essential for nocturnal species.

Policy blind spot: The legal vacuum around light pollution

Despite increasing evidence that ALAN negatively impacts biodiversity, India lacks a centralised legal or regulatory framework to mitigate its consequences. Unlike air and water pollution, light pollution is not formally addressed in India’s environmental governance. Its absence from pollution control regimes and planning norms leaves wildlife and ecosystems vulnerable, particularly in ecologically sensitive regions. The growing presence of high-intensity LED lighting, promoted under urban development schemes, exacerbates this problem by fragmenting habitats, disrupting biological rhythms, and increasing species mortality. Below are the key areas where Indian policy remains inadequate:

(1) Environmental laws and pollution control regimes

India’s existing environmental laws do not mention light pollution or ALAN as a form of environmental harm. As a result, light pollution is not treated as a regulated pollutant under Indian law. This creates a legal gap where institutions like the Central Pollution Control Board lack the authority to monitor or control light emissions, even when they harm biodiversity. Excessive or misdirected lighting is usually treated as an infrastructure or urban design issue, not an ecological threat. Without legal recognition, there are no mandatory standards, penalties, or impact assessments for lighting near sensitive zones such as wetlands, forests or wildlife habitats. This omission prevents proper regulation and weakens conservation efforts, especially in rapidly urbanising areas. Including light pollution in core environmental legislation is essential to ensure that it is addressed with the same seriousness as air, water or noise pollution.

(2) National Green Tribunal (NGT)

The NGT has acknowledged light pollution as an environmental concern, notably citing it as a contributing factor in the 2024 Navi Mumbai flamingo deaths. The Tribunal observed that newly installed LED lights impaired the birds’ vision, leading to fatal collisions. While this recognition is important, it has not translated into concrete legal or policy reforms. No binding guidelines, monitoring protocols, or regulatory standards were issued in the aftermath of the ruling. This reflects a broader challenge judicial observation, though meaningful, often lack sustained impact without legislative backing or administrative enforcement. For light pollution to be effectively addressed, NGT’s insights must be followed by clear mandates, regular oversight, and coordination among environmental and urban planning authorities.

(3) Environmental impact assessment (EIA)

The EIA process is a critical tool for regulating development, but it currently overlooks the issue of ALAN. Although the United Nations Convention on the Conservation of Migratory Species⁷ recommends evaluating lighting impacts for projects near ecologically sensitive areas, India’s EIA guidelines do not require any such assessment. Even infrastructure or tourism projects located near wetlands, riparian zones, and wildlife corridors receive clearance without accounting for the ecological effects of ALAN. Research by Khanduri et al. (2023) has shown that light-intensive developments can fragment habitats, alter animal movement and disrupt breeding cycles. This highlights a significant policy gap in India’s environmental assessment framework.

(4) International commitment under United Nations Convention on the Conservation of Migratory Species, 2024⁸

India, as a signatory to the United Nations Convention on the Conservation of Migratory Species, 2024 (CMS), is required to take concrete steps to mitigate threats posed by ALAN to migratory species. The CMS guidelines advise restricting high-intensity lighting within 20 km of ecologically sensitive areas like bird flyways and wetlands, promoting the use of warm-spectrum LEDs, directional lighting, and creating dark corridors to protect nocturnal habitats.⁹ However, these recommendations have not been meaningfully integrated into India’s national environmental laws or planning policies. This gap between international commitments and domestic implementation undermines both conservation efforts and India’s credibility in meeting its global biodiversity obligations. Aligning national frameworks with CMS protocols is crucial for protecting migratory wildlife and ensuring compliance with international environmental standards.

(5) Urban Development Schemes and Smart Cities Mission

India’s urban development programs, including the Smart Cities Mission, have encouraged the adoption of energy-efficient LED lighting to enhance safety, aesthetics and infrastructure.¹⁰ However, these upgrades have largely overlooked their ecological consequences. Lighting installations under such schemes are not subjected to environmental assessments that consider their impact on nocturnal wildlife or migratory species. There are no mandatory design guidelines to limit glare, skyglow, or light spill in ecologically sensitive areas. City development plans typically lack light pollution maps or wildlife-sensitive lighting protocols. As a result, cities are becoming increasingly inhospitable for species that depend on darkness for survival. Without integrating ecological considerations into urban lighting policy, these development initiatives risk exacerbating habitat fragmentation and biodiversity loss.

Towards a rights-based, community-centric approach

A forward-looking approach to mitigate light pollution must be rooted in legal accountability, community participation and ecological ethics. The conservation of darkness should be treated as an essential component of environmental sustainability. Recognising darkness as an ecological resource, much like clean air or water, can reframe public policy and urban planning priorities. Effective change requires coordinated reforms at national, municipal, and community levels, backed by scientific research and technological innovation. The following actions offer a multi-pronged solution:

(1) A national light pollution law

A 2023 study by Carolyn S. Burt and Jeffrey F. Kelly highlights how ALAN disrupts migratory patterns, reproduction and predator-prey dynamics, underscoring the urgent need for regulatory intervention.¹¹ In light of such findings, India urgently requires a dedicated light pollution law that sets luminance thresholds, and mandates light impact assessments for all major projects. The law should include enforceable standards for lighting in ecologically sensitive zones, specifying shielding, curfews, and wildlife-safe LED usage. Regulatory bodies like Central Pollution Control Board and Forest Departments must be empowered to monitor compliance and conduct regular lighting audits. Drawing from Spain’s Sky Law (2001), India can adopt zoning and lighting design regulations to protect dark habitats. Hanle’s Dark Sky Reserve in Ladakh is a commendable step but lacks replication without legislative support. The law should align with international commitments under the CMS and integrate with existing environmental laws and EIA guidelines. This would institutionalise light pollution governance and strengthen biodiversity protection.

(2) Public participation and awareness

While laws and policies are essential, meaningful change begins at the community level. Public awareness and behavioural change play a pivotal role in addressing light pollution, particularly in a culturally diverse country like India where festivals and decorative lighting are common. Awareness campaigns are critical to reducing excessive lighting, especially during celebrations and in residential areas. Schools, non-governmental organisations (NGOs), and civic bodies should promote the ecological importance of darkness through environmental education, night-time ecology modules, and community-driven initiatives like “turn off the lights” drives. Faith-based organisations and event planners should be encouraged to adopt low-impact lighting practices. Social media and digital platforms can also amplify awareness, especially among youth and urban communities. Voluntary lighting curfews and neighbourhood-level campaigns can build a shared ethic of sustainable illumination and help preserve nocturnal biodiversity.

(3) Urban planning and dark sky zones

As cities continue to expand, integrating ecological considerations into urban planning has become more urgent than ever. One effective strategy is the inclusion of dark sky zones designated areas where artificial lighting is strictly regulated to protect nocturnal ecosystems. These zones can be established near wetlands, forests, rivers, and even in agricultural belts where insect and bird activity is essential for pollination and ecological balance. City development plans must account for lighting intensity, placement and spectrum in these sensitive regions. Municipal lighting codes should strictly control high-mast lights, illuminated billboards, and decorative lighting that contributes to skyglow. Strategic tree plantations along roads and residential areas can serve as natural light shields, improving habitat continuity. Additionally, dark-sky compliance should be linked to urban development approvals to ensure long-term ecological resilience.

(4) EIA framework reforms

Despite being a fundamental component of ecological governance, EIAs continue to ignore the growing harm posed by ALAN. ALAN needs to be formally incorporated as a crucial criterion in the EIA procedure in order to facilitate comprehensive evaluation. Lighting evaluations, comprising light modelling, spectral analysis, and ecological effect simulations, should be required for infrastructure, tourism and industrial projects, particularly those located close to forests, wetlands, riparian corridors and wildlife sanctuaries. Long-term impacts on species behaviour, migration, and breeding patterns must be assessed in these research. In environmentally sensitive areas, guidelines should require the use of motion sensors, low-lumen and warm-coloured LEDs, shielded fixtures and time-based illumination curfews.

(5) Investment in technology, research and monitoring

In a nation like India that is gradually becoming more urbanised, light pollution must be properly mitigated by scientific innovation and data-driven administration. Both public and private infrastructure must use eco-friendly lighting technology like motion-sensor systems, amber LEDs, and fixtures that comply with the International Dark-Sky Association. Internet of things (IoT)-enabled lighting can drastically cut down on superfluous illumination by modifying brightness according to the time of day, weather and human activity. Long-term ecological research, satellite-based night sky monitoring, and geographic information system (GIS)-integrated mapping of light pollution to monitor urban light spread should all be supported by government financing. Academic institutions and conservation organisations must receive research grants in order to carry out field surveys and behavioural effect analyses particular to a species. Scalable lighting models that strike a compromise between ecological protection, and human requirements can be shown in pilot projects in biodiversity hotspots.

ALAN is not just a byproduct of modern development but an escalating ecological threat that endangers biodiversity, disrupts nocturnal life, and fragments natural habitats. Despite global recognition and scientific evidence, India’s legal and policy frameworks remain silent on this invisible pollutant. A coordinated national response rooted in legal reform, public awareness, and ecological planning is urgently needed to protect the night as a vital ecological resource.