Krishraj Singh Sikarwar and Princy Singh Sikarwar

Global night sky brightness increased by nearly 10% every year between 2011 and 2022, which is more than an astronomical inconvenience. Artificial light at night (ALAN) also has an adverse effect on human health and ecology yet it is barely regulated, almost entirely invisible in public health discourse, and profoundly unequal in its distribution. We argue that light pollution is in fact a right-to-health issue.

What light at night does to the body

The human body’s circadian rhythm—the internal 24-hour clock governing sleep, hormone release, immune function, and cellular metabolism—is calibrated by darkness. When ALAN enters the eye’s retinal ganglion cells after dark, it suppresses the release of melatonin, a hormone that is not merely a sleep signal but a critical modulator of immune function. During sleep, the immune system deploys melatonin to identify and eliminate abnormal cells produced during normal daily cell division. When that signal is disrupted night after night, the body’s defences quietly erode.

The consequences are serious. Blue-wavelength light—the dominant output of modern LED streetlights and digital screens—suppresses melatonin for twice as long as other wavelengths and displaces circadian rhythms by up to three hours. Chronic circadian disruption has been linked to depression, cardiovascular disease, diabetes, obesity, and metabolic syndrome. The International Agency for Research on Cancer (IARC) has twice classified night shift work involving circadian disruption as a “probable carcinogen”. Epidemiological studies show that people living in areas of high light pollution have elevated rates of breast, prostate, colon, and thyroid cancers.

Failing right to health obligations

General Comment No. 14 of the UN Committee on Economic, Social and Cultural Rights clarifies that the right to health extends to the underlying determinants of health including a healthy environment, and imposes on states an obligation to improve all aspects of environmental and industrial hygiene. Light pollution—a wholly anthropogenic, entirely preventable alteration of the nocturnal environment that demonstrably harms human biology—falls squarely within this remit. Yet it is conspicuously absent from national health strategies, from environmental regulation in most jurisdictions, and from the UN Sustainable Development Goals.

States are obligated to take deliberate, concrete steps toward full realisation of the right to health using maximum available resources. Regulating outdoor lighting—for example, mandating shielded fixtures, restricting blue-spectrum LEDs in residential zones, imposing curfews on commercial lighting—costs relatively little compared to the disease burden it could prevent. The absence of such regulation is not a neutral policy position; rather, it is a failure to meet an existing legal obligation.

Inequitable light pollution distribution

Light pollution is not distributed equally. An environmental justice study of the continental United States found that Black, Hispanic, and Asian Americans are exposed to approximately twice the levels of ambient light pollution as white Americans—a disparity that held across all income levels and persisted in both urban and suburban contexts. This disparity partly reflects the deployment of artificial lighting for nighttime policing and surveillance in minority communities, meaning that state infrastructure itself becomes a vector of health inequity and violates non-discrimination obligations in the ICESCR and principles of environmental justice.

Communities already experiencing elevated rates of asthma, cardiovascular disease, and limited healthcare access—conditions associated with poverty and race—are being subjected to a further, silent health hazard in the very hours when their bodies are supposed to recover. Wealthier residents, by contrast, retreat behind blackout curtains in neighbourhoods where the social desirability of dark nights is already reflected in property values and lighting ordinances.

A rights-based response  

DarkSky International argues that solutions are technically straightforward: shield outdoor fixtures so light falls downward rather than outward; replace high-intensity blue-spectrum LEDs in residential streets with amber alternatives; implement lighting curfews for commercial signage and industrial sites. These changes are cost-effective and reduce energy consumption; the obstacle is not technology. It is regulatory will.

A rights-based approach would require states to: recognise ALAN as an environmental health hazard under national public health frameworks; adopt disaggregated monitoring of light pollution exposure by race, wealth, and geography; prioritise remediation in communities already bearing compounded environmental burdens; and amend urban planning and energy regulations to reflect the biological imperative of nocturnal darkness.

Ironically, the infrastructure built to make cities safer is, night by night, degrading the health of the people who live in them—and especially so to those least able to seek protection. The body’s need for darkness is not a preference; it is a biological requirement as fundamental as the need for clean air or safe water. States have human rights obligations to address environmental threats to health and light pollution is one such threat.

Krishraj Singh Sikarwar is a second year BBA-LLB student at the School of Business & Law, Navrachana University, Vadodara, Gujarat, India.

Princy Singh Sikarwar is a fourth year BBA-LLB student at the School of Business & Law, Navrachana University, Vadodara, Gujarat, India.