Light Pollution: Rising Threat from Artificial Light at Night (ALAN)

Syllabus: GS3/Environment

Context

• A study published in the journal Nature has found that artificial light at night increased by 16% globally between 2014 and 2022.
  • The sharpest rise has been observed in Sub-Saharan Africa and Southeast Asia, with India and China emerging as major contributors in Asia.

What Is Light Pollution?

• Light pollution is the human-made alteration of outdoor light levels from those occurring naturally. In practical terms, it refers to unwanted, inappropriate, or excessive artificial lighting, primarily caused by Artificial Light at Night (ALAN). 
• It is increasingly recognised as an anthropogenic environmental pollutant. It is estimated that:
  • Over 80% of the world’s population lives under light-polluted skies;
  • Around 23% of Earth’s land area is affected by skyglow.

Causes

• Rapid urbanisation: Today, about 55% of the global population lives in urban areas, and this is projected to rise to 68% by 2050, significantly increasing the demand for outdoor lighting.
• Unregulated outdoor lighting: In poorly regulated systems (unshielded streetlights, billboards, façade lighting), 30–50% of emitted light is wasted upward or sideways, directly contributing to skyglow.
• Vehicle-induced light pollution: Rapid growth in vehicle numbers increases headlight glare and roadway illumination.
  • India has over 30 crore registered vehicles, contributing significantly to urban night brightness.
• Shift-based work: Expansion of 24×7 services (IT, healthcare, transport, manufacturing) leads to continuous lighting demand.

Impacts

• Human Health: Exposure to artificial light at night suppresses melatonin production, leading to insomnia and other health issues.
  • Chronic exposure to light pollution has been linked to increased stress and reduced cognitive performance.
• Environmental and Ecological: Nocturnal animals, migratory birds, and insects rely on natural light cycles.
  • Birds living in brightly lit areas tend to sing earlier at dawn and later at dusk, disrupting their natural rhythms and negatively impacting migration, feeding, and breeding patterns.
  • Similar effects occur in species like fireflies, whose communication suffers. Artificial lighting confuses navigation and feeding patterns.
• Astronomy and Scientific Research:  Brightening of the night sky hampers astronomical observations, especially near urban centers.
• Energy Waste: Billions of units of electricity are wasted annually due to poorly directed lighting, increasing carbon emissions.

Government Initiatives to Curb Light Pollution

• Energy Conservation Building Code (2017): The ECBC is a set of standards established by India’s Bureau of Energy Efficiency (BEE) to promote sustainable design and reduce energy consumption by 25–50% in new commercial buildings.
• Street Lighting National Programme (SLNP): Launched in 2015, to replace conventional street lights with smart and energy-efficient LED streetlights across the country.
• Smart Cities Mission: Adaptive lighting is a core component of India’s Smart Cities Mission, designed to optimize energy consumption and reduce light pollution by dynamically adjusting street lamp intensity based on real-time traffic and time conditions.
• Environmental Protection Act 1986: Provides umbrella power to the Central Government to regulate environmental pollution of all kinds.
  • Light pollution is not explicitly defined, but can be regulated as a form of environmental disturbance.

Conclusion

• Light pollution is an emerging environmental challenge driven by rapid urbanisation and unregulated artificial lighting.
• There is a need to formally recognise Artificial Light at Night (ALAN) as an environmental pollutant and integrate light pollution standards into urban planning, Environmental Impact Assessment (EIA), and biodiversity conservation frameworks.
• A balanced approach between development and ecological protection is essential, ensuring that night skies remain a shared natural heritage while safeguarding human health and biodiversity.

Source: TOI