The disclosure of Hong Kong's 'maximum' carrying capacity was first made in 1984 by the then Principal Government Town Planner J. M. Wigglesworth at a conference on urban growth. 'Sub-regional studies have indicated recently that there is sufficient land potential to house 10 million people at current densities, 4.5 million in the metropolitan area alone,' he said.

It is not certain what were the precise density levels to which Mr Wigglesworth was referring, but the Government's annual report for 1984 said the population density of the metro area, encompassing Hong Kong Island, Kowloon, New Kowloon and Tsuen Wan, was 28,479 per sq km in 1983. In the most crowded district of Shamshuipo, the density level was 165,445 per sq km.

Since then, urban population density dropped to 26,180 per sq km last year because of migration to the New Territories, where the density level rose from 792 per sq km to 2,790 per sq km between 1983 and 1993.

Under the Metroplan, the size of the metro area will grow from 6,500 ha to 8,500 ha by further harbour reclamation, but its population will be kept at 4.2 million, meaning density there will decrease further.

But there is no escaping the fact that Hong Kong will remain a high-density city with multi-storey blocks each housing thousands of people - enough to fill a suburb in a lower-density city.

The latest news from the Census and Statistics Department indicated that Hong Kong's population had grown by 2.4 per cent during the 12 months to June to reach 6,061,400 - a figure previously forecast to not become reality until 2000.

The higher than expected rate of increase compared with the 1.8 per cent recorded between June 1993 and June 1994, and was attributed to growing numbers of emigrant returnees, foreign domestic helpers, Chinese nationals and expatriate workers.

Although Hong Kong families are having fewer and fewer children, the population is expected to continue to grow because of immigration, primarily from China for family reunions. Simple calculations reveal that if Hong Kong's population continues to grow at a modest two per cent per annum, then by 2020 the community will number at 10 million.

This may have set off environmentalists' alarm bells, but according to Mr Wigglesworth's present-day successor, Dr Ted Pryor, there is no need for us to panic.

Based on current assessments, Dr Pryor said Hong Kong could accommodate seven million to eight million people. Even more could be housed if we were prepared to overcome certain constraints on the availability of land.

And since we did not know what technology could do, 'there is no absolute upper limit' on how many people Hong Kong could accommodate, he said.

The learned town planner, who has played a key role in planning Hong Kong's growth in the last 30 years, said the question of how many people the territory could accommodate could be split into two: how many do we want, and how many we may have to accommodate anyway.

Between the 1950s and 1970s, Hong Kong was subject to successive waves of large-scale immigration from China, giving planners no alternative but to find more land to house a rapidly growing population.

WHILE unregulated immigration has since been brought under control, Hong Kong as an international city has seen a tremendous increase in the number of expatriates in the last 10 years.

As to the question of how many people Hong Kong wants to have, a lot depends on political decisions and what we can afford.

Dr Pryor said the physical capacity to accommodate people was a function of suitable planning involving such factors as the availability of land, development density, state of technology and architectural design.

A dig into the archives reveals why Dr Pryor should feel proud of his past and present colleagues' achievements in coping with the exponential growth of Hong Kong in the last 50 years.

In 1956, the opening chapter of the Government's annual report, entitled A Problem of People, recorded the administration's early efforts to cope with the influx of tens of thousands of refugees fleeing from China's civil war.

It noted that Kong Kong, which then had a total area of about 391 sq miles (1,013 sq km), of which only 62 sq miles was immediately available, had a 'normal capacity' to accommodate only 1.2 million. But by the mid-1950s, it was home to more than 2.5 million.

Forty years on, Hong Kong's land area has grown to 1,078 sq km thanks to massive reclamation projects, and its population has increased almost fourfold to more than six million.

Nevertheless, although conditions in some parts of the territory are still undesirable, the overall quality of life has improved with the benefit of technological advances and good planning.

Dr Pryor said: 'We have got to a point now that high-density living is not a thing to be feared.' On the contrary, in fact. Dr Pryor opined that low-density population was problematic, citing the sprawling cities of Los Angeles and Melbourne as examples where air pollution was serious because of heavy traffic.

In many low-density cities, the poor were confined to the inner city areas and had to commute to work in factories way out from the urban centre, he said.

Dr Pryor said the wonder of high-density living was that it saved on land use and made financially viable the development of infrastructure facilities such as public transport, water supply, drainage and telecommunications.

'High density works well as long as you have good design, management and maintenance,' he said.

Given that the territory is a small place, Dr Pryor admitted that Hong Kong people would not be able to enjoy the sense of space taken for granted in places endowed with more land.

But he said the environment in the new towns was extremely good, and living conditions were pleasant in newly completed residential estates in the urban areas such as South Horizons and Laguna City, which had sports and recreational activities and landscaped gardens.

'As a compact city, one is never too far away from the country parks, which comprise half of the territory,' he added.

Dr Pryor said the territory still had a great reservoir of land and the key to developing it was infrastructure. While harbour reclamation had almost reached its limit, there was still much scope for this method of producing land in Tseung Kwan O and north Lantau.

A large amount of private agricultural land could also be utilised because the economics of Hong Kong did not favour agriculture any more.

Dr Pryor said the Territorial Development Strategy had examined the environmental capacity of each area. The Tolo Harbour area, for example, has three big limitations that put a cap on the number of people it can accommodate: the harbour is largely enclosed, making it susceptible to pollution; the limited capacity of marine water to absorb nutrients in treated sewage could lead to algae growth that causes red tides; and road and rail links in the area have been filled to capacity by cross-border traffic.

In the northwestern New Territories, there is greater capacity for high air quality, but sewage treatment and ecological considerations are constraints.

But Dr Pryor said that if we were faced with pressure from population growth, we would have to decide if such constraints could be overcome.

For example, sewage treatment facilities could go underground, as could reservoirsand refuse transfer stations, while the use of fuel oil and road traffic could be regulated to contain air pollutions.