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Sudhakar Windows and Doors

Reducing Light Pollution from Building Glass Façades and Fenestrations

By: Tanya Kaur Bedi, Indian Institute of Technology, Kharagpur

The increase of artificial light at night, contributing to the phenomenon of light pollution, is an escalating concern amid global urban development. Numerous cities now boast a luminous sky visible from considerable distances, showcasing the foremost manifestation of light pollution, characterized by excessive or misdirected artificial light. Light pollution poses significant threats to human health, impacting various physiological and psychological aspects. Exposure to artificial light during the night disrupts circadian rhythms, leading to sleep disturbances and insomnia. The suppression of melatonin production, particularly by blue light emitted from electronic devices and outdoor lighting, contributes to an increased risk of certain health issues, including cancer.

Light pollution has transcended local boundaries to become a worldwide issue
Light pollution has transcended local boundaries to become a worldwide issue

Moreover, prolonged exposure to bright artificial light is associated with heightened stress and anxiety levels, potentially leading to mental health disorders such as depression. The impact extends to ocular health, causing discomfort, eyestrain, and potential vision problems. As a researcher, it is crucial to explore the specific mechanisms through which light pollution influences human health, citing relevant studies and proposing mitigation strategies.

Architects, urban planners, and lighting designers can collaboratively address and reduce light pollution
Architects, urban planners, and lighting designers can collaboratively address and reduce light pollution

Additionally, acknowledging the indirect effects on wildlife and ecosystems can provide a comprehensive understanding of the broader implications of light pollution. Recent urban development trends have ushered in a surge of artificial light at night, primarily for amenity or security lighting purposes. This surge has substantially transformed the nocturnal landscape & luminosity of urban areas.Light pollution has transcended local boundaries to become a worldwide issue, progressively diminishing the ability to observe stars and instigating a range of environmental and energy challenges. Its components include glare, heightened unnecessary illumination, temporary lighting, and unforeseen fluctuations in lighting levels Diverse sources such as streetlights, fishing boats, buildings, vehicle headlights, and even lights on under-sea research vessels collectively contribute to the creation of a domical sky glow, among which reflective building Façades and light through fenestrations are major contributors in urban areas.

The impact of building glass Façades and fenestration design on urban environments extends beyond aesthetics
The impact of building glass Façades and fenestration design on urban environments extends beyond aesthetics

Additionally, Artificial Light at Night (ALAN) has also been linked to energy wastage, urban heat islands, and, air pollution, further emphasizing the intricate web of consequences associated with excessive night-time illumination. The use of glass in Façade and fenestration design has become increasingly popular in modern architecture due to its aesthetic appeal and functionality.

However, the extensive use of glass poses challenges in terms of light management, particularly in urban environments where artificial lighting is prevalent.

These contribute to light pollution through various mechanisms, buildings with glass Façades often use exterior lighting for illumination or decoration, which can add to light pollution if not properly controlled or directed; the transparency of glass allows internal lighting to be visible from the exterior, contributing to glare.

Glass surfaces can reflect artificial light, amplifying its intensity and contributing to light pollution in surrounding areas. Architects, urban planners, and lighting designers can collaboratively address and reduce light pollution, specifically in the context of building Façades and fenestrations, through the following strategies:

  • Minimizing Decorative Lighting: Controlling and regulating the use of decorative exterior lighting in architectural structures as a means to diminish light pollution can be helpful.
  • Directional Lighting Design: Opt for selective and directional lighting that minimizes upward or outward light spillage. Use fixtures with shields or hoods to direct light where it is needed.
  • Smart Fenestration Planning: Integrating smart fenestration systems that control the amount of natural and artificial light entering buildings based on time and environmental conditions. Utilizing window films or coatings that reduce glare and limit light reflection into the surrounding environment.
  • Selective Glazing: The use of selective glazing materials can help control the amount of light transmitted through windows while reducing reflectance.
  • Low-E Coatings: Low-emissivity (Low-E) coatings can be applied to glass surfaces to reduce both heat gain and reflectance, thereby improving energy efficiency and visual comfort.
  • External Shading Devices: External shading devices, such as louvres or overhangs, can be incorporated into Façade design to reduce direct night light penetration and minimize glare for occupants indoors.
  • Building Materials: Choose building materials with low reflectance to reduce the scattering of light, and contribute to a darker urban environment during the night.
  • Adaptive Lighting Control: Implement advanced lighting control technologies such as dimmers, timers, and motion sensors to regulate artificial lighting levels. Adaptive lighting systems that adjust intensity and colour temperature according to the time of day, occupancy or specific activities.

The impact of building glass Façades and fenestration design on urban environments extends beyond aesthetics, profoundly influencing light pollution levels and reflectance properties. By employing thoughtful design strategies, architects and urban planners can mitigate light pollution, enhance urban sustainability, and create more liveable cities. Balancing the aesthetic appeal of glass Façades with the need to optimize reflectance is essential for sustainable urban development in the 21st century.

Effective light management necessitates a multidisciplinary approaches
Effective light management necessitates a multidisciplinary approaches

The design of building glass Façades and fenestrations significantly influences the quality of urban environments, particularly concerning light pollution and reflectance. Innovative design strategies and technologies empower architects and urban planners to address these issues while crafting sustainable and visually appealing spaces.
However, effective light management necessitates a multidisciplinary approach that considers both environmental and human factors. Ongoing research and collaboration are essential to tackle such challenges. The contribution of building Façades to light pollution at night is a significant concern in urban environments. Exploring strategies to mitigate the adverse effects of illuminated Façades on light pollution is crucial for promoting sustainable urban lighting practices.


  1. Hatori, M., Gronfier, C., Van Gelder, R.N. et al. The global rise of potential health hazards caused by a blue light-induced circadian disruption in modern aging societies. npj Aging Mech Dis 3, 9 (2017). https:// 2
  2. Shariff, N N M & Hamidi, Zety & Faid, Muhamad Syazwan. The Risk of Light Pollution on Sustainability. ASM Science Journal. 12. 134 (2019).
  3. Bedi, T.K., Puntambekar, K. & Singh, S. Light pollution in India: appraisal of artificial night sky brightness of cities. Environ Dev Sustain 23, 18582–18597 (2021). s10668-021-01384-2
  4. Bedi, T.K., Puntambekar, K. & Singh, S. Assessment of Light Pollution in Indian Scenario: A Case of Bangalore. J. Inst. Eng. India Ser. A 102, 657–672 (2021). s40030-021-00530-3

Tanya Kaur Bedi, Indian Institute of Technology, Kharagpur


Tanya Kaur Bedi has an extensive academic background in architecture and environmental planning, culminating in a PhD from the Indian Institute of Technology (IIT), Kharagpur. Tanya has achieved notable accolades throughout her professional journey, including being a Gold Medallist from NIT Bhopal and receiving the CSIR and SERB Grants from the Government of India. She specializes in devising solutions for challenges such as declining indoor air quality and light pollution, with a focus on the health and well-being of building occupants. She has effectively disseminated her research findings as a published author in reputable journals and by presenting her work internationally in the United States, China, Portugal, and others. Through these, Tanya has contributed to the global discourse on built-environment issues.

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