In the evening, as one ventures out in Bangkok, the city’s towering billboards and their brightly lit screens stand out just as much as its looming skyscrapers. These massive displays cast an intense glow, sometimes dazzling nearby drivers and pedestrians. Some of the city’s highways are fully covered on the sides with rows of these dazzlingly lit-up billboards displaying their consumerist wares. 

With Bangkok’s expansion into a bustling metropolis, its bright city lights illuminate more than just its nightlife and restaurants, roads, and landmarks. They are also contributing to an emerging environmental concern: light pollution. While the city’s vibrant nightlife and bright skyline boost tourism and commerce, artificial light pollution is having adverse effects on human health and the environment. Beyond health concerns, light pollution is also tied to excessive energy consumption, contributing to greenhouse gas emissions and hampering climate change adaptation efforts. 

Light pollution in Bangkok

Light pollution, defined as excessive or misdirected artificial light, has been a growing issue in major cities worldwide, and Bangkok is no exception. With rapid urbanization, expanding infrastructure, and increasing reliance on illuminated streets, billboards, and commercial centers, the city has become a hotspot for skyglow-the brightening of the night sky due to artificial light.  

According to the New World Atlas of Artificial Night Sky Brightness ^1, over 80% of the world lives under light-polluted skies. The Milky Way is hidden from more than one-third of humanity. In Thailand 61.5 % of the population stays 50% above the natural level of light, under which the stars are no longer visible (87 to 688 μcd/m2).  

Bangkok is becoming one of the contributors to this alarming trend. According to David Lorenz’s Light Pollution Atlas 2022^2, Bangkok’s inner areas reach a skyglow level of 9 on the Bortle Scale, signifying extreme light pollution, while the outer regions range between levels 7 and 8. The city’s sprawling light networks, commercial centers, and 24/7 activities have pushed it onto the map of increasingly light-polluted areas in Southeast Asia.

The hidden costs of the unending glow 

The environmental and human health risks associated with light pollution are often overlooked. Research has shown that the health impacts of light pollution have been broadened from sleep disorders^3 to chronic health issues.  

Melatonin, a hormone released in response to low light levels, regulates sleep cycles and is suppressed by excessive light at night. The disruption of melatonin interferes with circadian rhythms, which can lead to various health issues including sleep disturbances, weakened immune function, increased risks of obesity, diabetes, mood disorders, cardiovascular diseases, reproductive problems, and hormone-related cancers.  

Beyond human health, light pollution also has dire consequences for the ecosystem. ^4

Nocturnal animals, such as bats, migratory birds, and insects, rely on the natural cycles of day and night for navigation and feeding. Artificial lights disrupt^5 these natural behaviors, often leading to disorientation, altered migration patterns, reproduction behaviors, and increased mortality rates.  

A study of blackbirds (Turdus merula)^6 in Germany found that artificial night lighting causes birds in the city to become active- waking and singing as much as five hours earlier than birds in natural areas. Similarly, studies conducted on river ecosystems have shown alteration in species diversity^7 and behavior in areas where artificial light is prominent at night, and similar trends may emerge in Bangkok’s Chao Phraya River unless mitigation measures are taken. 

In the dark: the legal framework on light pollution in Thailand 

Despite its growing significance, light pollution remains a largely unaddressed area in Thailand’s legislation.  

The Thailand Enhancement and Conservation of National Environmental Quality Act, B.E. 2535 (1992) recognizes light as a pollutant that can negatively affect environmental quality and public health, but there is no specific provision to regulate excessive artificial lighting.  

Similarly, the Public Health Act, B.E. 2535, which defines nuisances, includes light intrusion but fails to classify Artificial Light at Night (ALAN) as a statutory nuisance, leaving the enforcement of such regulations largely subjective. Moreover, while the Bangkok Municipal Regulations Relating to Building Control B.E. 2001 set indoor lighting standards, they do not address outdoor lighting.  

The Energy Conservation Promotion Act B.E. 2535 (1992) focuses on energy-efficient lighting within buildings, leaving public spaces and outdoor lighting unregulated. 

Global solutions to light pollution 

Countries and cities worldwide are adopting innovative strategies to reduce light pollution while improving energy efficiency and protecting ecosystems.  

• Flagstaff, Arizona, a designated Dark Sky City has a fully shielded streetlight directing downward, minimizing skyglow.  

• Madrid, Spain, and Berlin, Germany, replaced old and blue light streetlights with energy-efficient, warm-toned LEDs and implemented dimming techniques for late-night hours.  

• In France, strict laws mandate that non-residential buildings turn off lights between 1 AM and 6 AM, conserving energy and reducing unnecessary lighting.  

• Sydney, Australia, and the UK, Exmoor National Park focus on wildlife protection by using low-intensity and shielded lighting near-natural habitats.  

• Amsterdam, Netherlands, uses smart street lighting that adjusts brightness based on real-time traffic, reducing unnecessary light and conserving energy. These global efforts are helping to mitigate light pollution and protect the night sky.

Less light, darker nights are the path forward 

Addressing light pollution in Bangkok requires a multi-pronged approach. Several global cities, such as Paris and Hong Kong, have already introduced light curfews and dimming programs for non-essential lights at night.  

Bangkok could take inspiration from these models by implementing regulations that encourage energy-efficient and well-directed lighting.  

Public awareness campaigns are needed to inform citizens about the health and environmental impacts of excessive artificial light. More smart lighting solutions in public spaces, and adopting urban planning strategies that consider the placement and intensity of lights can help balance illumination needs with reducing light pollution. 

Bangkok must also ensure its progress does not come at the expense of its natural environment and public health. Light pollution may seem minor to some, but its effects are far-reaching.  

By learning from global best practices and implementing targeted measures, Bangkok can safeguard its night skies, protect its ecosystems, and improve the well-being of its residents. The city has the opportunity to lead the way in Southeast Asia, proving that a modern metropolis can coexist with a sustainable, star-lit sky.