Let's find a balanced approach to lighting

Light pollution might be tolerated in Hong Kong if it is caused by technology that reduces the amount of electricity used and, as a result, improves air quality. But the term has been redefined by a new energy-efficient product that has created another environmental problem - too much artificial light.

Light-emitting diodes that use less power to produce brighter and more elaborate advertising billboards, giving advertisers a bigger bang for their buck, enhance the city of light for tourists and sightseers, but not the quality of life for many residents.

The latest LED display to upset nearby residents and green activists with its directional, concentrated light stands atop the new The One mall in Tsim Sha Tsui, close to others on iSquare and Star House. One advertising agent predicts that all illuminated signs in the city will be LEDs within a decade, compared with 1 per cent a year ago and 3 to 4 per cent now.

They are not the only culprits. Complaints about intrusive commercial lighting, that can turn patches of night into day and illuminate an apartment like a disco, rose from 87 in 2007 to 377 last year - or more than 400 per cent, and are still rising.

The government has responded by ordering a public consultation on external light pollution, followed by a study commissioned by the Environment Bureau, the findings of which it is still digesting. Given that LEDs can only make the problem rapidly worse, some practical ideas are needed to balance legitimate competing interests, so that a renowned symbol of the city's vibrancy - a spectacular nighttime skyline - is not dimmed, nor the rhythms of people's lives unduly disrupted.

That resonates with the mixed feelings of green activists who welcome LED lights for saving power, but are concerned about the potential for severe light pollution in a city already blighted by poor urban planning. If LEDs prompt some effective action on light pollution, that will enhance their environmental credentials.

A recent study by the University of Hong Kong found that urban night skies can be up to 500 times as bright as those in the countryside, and LEDs are not to blame for that. It reflects the fact that, too often, lights on buildings, illuminated signboards and in shop windows are too bright, poorly designed and left on overnight for no good reason, wasting energy and contributing to air pollution.

Wasteful lighting has played a part in the rise in energy consumption far outstripping the population increase - 25 per cent for energy compared to 4.3 per cent in population from 1997 to 2004, for example. It is not only an eyesore but can affect people's natural body rhythms, sleep and health.

That said, Hong Kong remains the city of lights. Its nighttime skyline is one of the things sets it apart and is what tourists expect to see. It is therefore an asset that needs to be sympathetically managed.

Encouraging an industry dedicated to providing environmentally and socially responsible lighting would be a good starting point. More needs to be done to win the co-operation of building and shop owners and advertising executives.

Billboard designs that comply with principles of sustainable development, and self-regulation of the brightness of signs during late-night hours, might not sit easily with robust competition for business. But they are sensible suggestions for heading off a clamour for official regulation.