As a city famous for its towering cityscape, Hong Kong has long been a monument to the concept of modern, high-rise living. But debate about a recent project in Yuk Yat Street in To Kwa Wan reflects the growing concern in some circles about the conflicting goals of property developers and planning authorities over residential construction projects. Minutes of a recent Town Planning Board meeting show members approved an application to add several 50-storey residential high-rises to the To Kwa Wan waterfront. The June meeting heard some board members express reservations, largely about the height of the construction. They said it would be incompatible with the local surroundings, as existing buildings in the area were only about 10 storeys high. Those members were also concerned that the final plan would create a wall effect if the developer built the blocks in a row to maximise the number of flats with sea views, instead of dotting them irregularly across the site in the traditional way. Despite the misgivings, the project gained the board's approval. Although it was incompatible with most of the buildings in the neighbourhood, the developer's plan matched a neighbouring development that the board had already approved. According to minutes from the meeting, the chairman of the board's metro planning committee, Bosco Fung Chee-keung, who is also the planning director, said that since the application had been deferred once by the committee, a further deferral might be unfair to the developer. The recorded discussion highlights two pressing planning issues confronting Hong Kong: buildings are getting taller and more of them are packed into lines in an effort to maximise the number of units offering the best view, with the latter trend creating a wall effect in the surrounding community. The wall effect slows down air ventilation, making the city even hotter in summer. Ng Mei-kam, an associate professor teaching urban planning at the University of Hong Kong, said the issue was very real for Hong Kong authorities and developers. 'High-rises and wall-effect high-rises are making Hong Kong hotter and hotter because they upset air ventilation,' she said. 'Vehicle emissions are another contributor to the urban heat island effect. So districts such as Mongkok, Tsim Sha Tsui and Central, where there are many high-rises and busy traffic, are hotter.' Hong Kong Institute of Architects vice-president Vincent Ng Wing-shun said the average height of residential blocks was now 50 storeys, and many of them were built on a podium that housed car parks, a clubhouse or shops. 'The podium makes the high-rises even taller,' he said. Residential projects in the 1980s tended to be 30 storeys high and then the average height reached 40 storeys in the early '90s, Mr Ng said. Hong Kong entered the new millennium with few residential blocks taller than 50 storeys. Cheung Kong Holdings has since prided itself on the construction of its 73-storey Harbourfront Landmark project on the Hunghom waterfront, calling it 'the highest waterfront development in Hong Kong'. No comprehensive account of the city's tall-building debate should discount the High Cliff development on The Peak. The 73-storey residential towers were erected on Stubbs Road and the slender, shiny structures easily stand out from the rest of the buildings in the neighbourhood. Since the buildings are on a redeveloped site, the decades-old lease was unrestricted, having been drawn up in an era when the idea of government imposing height restrictions was alien. Mr Ng attributed the trend towards ever-higher skyscrapers to the fact that development sites were getting bigger, which resulted in more permitted floor area for each project. 'Flats at higher floors have better views, so they can fetch a higher selling price,' he said. 'When the sites get bigger, developers have more flexibility. As a result, developers opt for 10 buildings 50 storeys high instead of 20 blocks 30 storeys high.' Mr Ng said building and planning authorities introduced policies a few years ago promoting 'green features' in residential developments, meaning environmentally friendly structures such as balconies and sky gardens became more common. The change brought with it extra permitted floor space, resulting in bulkier buildings. Mr Ng estimated the green-features policies had added at least 20 per cent in gross floor area to residential projects. But he said tall buildings did not present the same threat to the urban environment as the increasingly common wall effect. 'They are visually undesirable, such as by breaching the ridge line, and they are incompatible with the atmosphere of the neighbourhood,' he said. 'But they are not the biggest threat to our environment. The biggest worry is that more and more residential projects are built in a line that creates a wall effect in the community, blocking air and light.' A prime example of residential blocks built in a line in order to maximise sea view is Sino Land's waterfront development, One Silver Sea at the Olympic Station. The growing unease over the size and dominance of high-rise projects was underlined two weeks ago by an environmental group's campaign against four Kowloon-Canton Railway Corporation residential developments. Green Sense chairman Roy Tam Hoi-pong said the KCRC blueprint for residential developments at Yuen Long station, Nam Cheong station, Tai Wai maintenance centre and Tai Wai station all encouraged developers to build 40- to 52-storey buildings. He demanded the KCRC reconsider details of the projects. The four projects will all involve high-rises situated in a line above or on land near the KCRC railway stations. 'The KCRC developments will have the residential blocks built like a screen, cutting a community in two,' Mr Tam said. At Nam Cheong station, the building of 11 50-storey high-rises will create a 300-metre wall at the waterfront, significantly reducing the air and sunlight reaching the older, 10-storey buildings of Shamshuipo. The government-owned rail corporation said the Tai Wai maintenance centre construction contract had been awarded to Cheung Kong Holdings, and because a contract had already been signed, it was impossible to change the plan. Although the KCRC has not yet sought tenders for the Yuen Long, Nam Cheong and Tai Wai station projects, any significant changes to the design to reduce the wall effect would reduce the developments' density and profitability. A KCRC spokeswoman said the Yuen Long and the Nam Cheong station properties belonged to the government and any changes to the plan would have to be approved by the government. Analysts suggest the problem of increasingly tall buildings could be tackled by imposing height restrictions on districts or on particular development sites. Such measures have been imposed on Kwun Tong and Kowloon Tong. The government is working on the concept of restrictions for particular areas, although it is expected to take years to complete the exercise. The government hastened efforts to look at the issue after the recent saga involving the Grand Promenade development, in which former buildings chief Leung Chin-man was embroiled in a row over a grant of extra floor space to the Henderson Land project. Since early this year the Town Planning Board has reviewed every outline zoning plan to examine if there are development sites needing height restrictions. However, Mr Ng said that there was no law against creating a wall effect. The Building Ordinance includes guidelines on the size of windows for residential developments, but does not regulate air ventilation between apartments, and offers no safeguards on the amount of sunlight entering an apartment complex. 'The law only concerns the welfare of the constructed apartments, it isn't about the welfare of the community,' Mr Ng said. The Town Planning Board can ask developers to submit air-ventilation assessments in its scrutiny of plans, and the board may impose air assessment as a condition. But it only applies to sites zoned as a 'comprehensive development area'. Those zoned as high-density residential developments are not affected by this rule. The Housing, Planning and Lands Bureau and the Environment, Transport and Works Bureau issued a joint technical circular on air-ventilation assessment last month. It requires all major government projects to conduct an air-ventilation assessment test. The planning department included an air-ventilation test in the non-binding urban-design guidelines, but since it is voluntary, critics say it will not improve the situation. So far, the government has no plan to extend the test to the private sector. One solution to the problem, Mr Ng suggested, was lowering the development density of each residential development to improve the environment. But he said the issue could only be resolved if the government took on regional planning. Former president of the Hong Kong Institute of Engineers, Greg Wong Chak-yan, did not support the idea. 'It is not feasible,' he said. 'It will have [a] significant implication on government revenue.' He said that if there was an across-the-board reduction in development density, the measure would be unfair to existing buildings and the government would invite legal challenges. Mr Wong, who is also a member of the Town Planning Board, said there should be a balance between the rights of the community and development rights.