n 1989, the Hong Kong government realised that Hong Kong was in danger of becoming a vast, densely populated city. Due to the growth of the economy and business sectors, the water, waste and air pollution cause an adverse effect on the balance of ecology in Hong Kong.
Factories, farms and restaurants in the New Territories dump large amounts of sewage and even untreated waste into the streams and the sea. It makes the New Territories' streams be 'no better than open sewers'. This severe damage is irreversible and the creatures in the sea are the direct victims of the capitalised city’s effort.
The pink dolphin is one of the victims. Under threat from chemical pollution, increased sea traffic and the destruction of much of the natural shoreline for land reclamation, the number of pink dolphins has dramatically declined as the city continues to develop.
The nature reserve and birds in Mai Po Marsh are the other victims. They are threatened by the pig sewage flooding as well as the increased pollution from Shenzhen. Yet according to WWF Hong Kong the number of the endangered black-faced spoonbills wintering in Mai Po has risen from roughly 35 in the late 1980s to 152 after 10 years. About 400 are spotted after 2000. Estimates on how many of these birds remain in the wild vary from 2,000 to 1,000.
The oyster farms have been throttled by a mixture of pollution and competition from cheaper oyster cultivation across the border in China.
Air pollution is another serious problem. Air pollution has got noticeably worse since the late 1990s, with smoggy days becoming increasingly regular. Smoke-belching factories, ceaseless construction and large numbers of diesel vehicles have made for dangerous levels of particulate matter and nitrogen dioxide. Not only the flora and fauna are affected but also humans. Cases of asthma and bronchial infections have soared in recent years, and doctors place the blame squarely on poor air quality.
According to a Baptist University study, daily average minimum temperatures have increased by 0.02°C annually between 1965 and 2003, due to the "concrete jungle" which traps heat during the daytime and releases it at night. Average daily maximum temperatures have fallen by 0.014°C each year, as air pollution is blocking solar radiation. Resulting increased night time ambient temperatures incite families to use domestic air-conditioning, which further compounds the problem.
Research has shown that the ambient air-temperature in urban areas can be some 5°C higher than non built-up areas. The Hong Kong Polytechnic University commissioned NASA to take a high-resolution thermal image of urban Hong Kong by satellite at 10:40 pm on 4 August 2007, which showed at least a 4-degree difference between the coolest areas and the "urban heat islands". The variations are attributable to greater absorbency of man-made materials, and building density which restrict air-flow. The urban heat island had expanded into Hung Hom since January, when the first image was taken.
There has been increasing concern since 2006 over the "wall effect" caused by uniform high-rise developments which adversely impact air circulation. Due to the density of Hong Kong's population and the economies of scale of mass developments, there is the tendency of new private tower block developments with 10 to over 100 towers, ranging from 30-to-70-storeys high. Developers of housing estates are financially motivated to maximise the view, at the expense of the free-flow of air. Huge wall-like estates along the waterfront are often constructed.
In-fill developments will tend to done by smaller developers with less capital. These will be smaller in scale, and less prone to the wall effect.
Environmental group Green Sense, expressed concern that their survey on 155 housing estates found 104 have a 'wall-like' design. It cited estates in Tai Kok Tsui and Tseung Kwan O as the "best examples". In May 2007, citing concern over developments in West Kowloon, and near Tai Wai Yuen Long railway stations, some legislators called for a law to stop developers from constructing tall buildings which adversely affect air flow in densely populated areas, but the bid failed. In 2007, residents of Tai Kok Tsui, increasingly aware of the problem, have been lobbying against further proliferation of such high-rises in their area which threaten the last air corridor.