Have you ever seen a starry night in Hong Kong?
The poor visibility of night sky is due to the fact that Hong Kong has become the most light-polluted city in the world.
According to a study by the faculty of science at the University of Hong Kong, the night sky above Hong Kong’s urban area is as much as 1,000 times brighter than the international dark sky standard.
Light pollution in Hong Kong not only obscures the night sky, but also causes light nuisance, which may lead to potential health hazards, and threaten the ecosystem; however, it is possible that increase in nighttime electricity tariff, installation of automatic lighting control system, and legislation can help altering the situation.
Light pollution refers to the situation when light emitted from excessive artificial outdoor lighting are scattered by clouds, fog, and pollutants like suspended particulates in the atmosphere and brighten the night sky.
Since 2009, the Environmental Protection Department (EPD) has been receiving around 200 complaints against external lighting annually.
The increasing public concerns about the problem of excessive outdoor lighting has urged the government to set up the Task Force on External Lighting to tackle the problem.
In the assessment of impacts on external lighting conducted by the task force, the assessed values on glare, sign luminance, building facade luminance and light trespass level in Mongkok were all beyond the suggested limit according to the International Commission on Illumination (CIE).
According to a survey conducted by the Department of Physics at the University of Hong Kong, the level of light pollution in Tsim Sha Tsui is 1200 times brighter than a normal dark sky, which is the worst reading in the world.
The main cause of light pollution in Hong Kong is the excessive and improper use of artificial outdoor lighting by business corporations, such as over-illumination of neon signs, signboards, facades, shop fronts and video walls.
Corporations do not have enough awareness on energy conservation.
They have no incentive to control energy consumption as electricity companies offer a different tariff-charging scheme for corporations, providing lower charges for customers who have higher energy consumptions.
One of the examples is the High Load Factor Rider offered by China Light & Power Company.
The government also imposes no laws to regulate excessive lighting currently. The existing guidelines for external lighting installations set up by the Environment Bureau have weak deterrent effect.
Excessive lighting waste energy.
Excessive lighting brightens the night sky, decreases the contrast in brightness between the sky and stars, and thus reduces the number of stars visible in the sky.
Excessive lighting disturbs the ecosystem by interfering physiological cycles and movements of animals, such as disorient the nocturnally migrating birds, and affect the egg-laying behavior of sea turtles.