The sustainable city
FoundationA sustainable city meets its people's needs without wrecking the environment or the future — through greening, mass transit and compact vertical development. Hong Kong's transit-based travel and Singapore's Garden City are models.
- Sustainable city: environment, economy and society in balance
- Greening: Singapore's Garden City nears 50% green cover
- Transit: about 90% of Hong Kong trips ride public transport, keeping per-capita carbon low
文體小知識：方案評估課：用「綠化、公共交通、高密度垂直發展」三件套評估一個城市是否可持續，香港與新加坡是現成例子。
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1A sustainable city meets today's needs for housing, mobility and life while cutting pollution and resource use, so future generations inherit a liveable city too. It stands on three pillars — environment (low-carbon, liveable), economy (dynamic, employed) and society (fair access to housing and services).
2Greening comes first: parks, street trees and green roofs cool the city, absorb carbon dioxide and filter the air. Since the 1960s Singapore's 'Garden City' plan has pushed green cover to nearly half the island, now upgraded to a 'City in Nature' with linked park corridors; vertical greenery and rooftop farms let buildings breathe.
3Mass transit is the second tool: per passenger, trains and buses use far less energy than cars. Hong Kong has one of the world's highest public transport shares — about 90% of daily trips — anchored by the MTR; electric buses, cycle tracks and studies of electronic road pricing push emissions lower. Singapore's Certificate of Entitlement (bid for the right to own a car) and road pricing keep vehicle growth in check.
4Compact vertical development is the third: concentrating people in tall buildings along rail lines saves land for countryside and farms and makes walking to stations easy. Hong Kong's 'Rail plus Property' model grows new towns along the railway; Singapore's HDB flats house about 80% of the population in towns with schools, markets and parks. Density has its dangers — crowding and the urban heat island — so ventilation corridors and open space matter. The sustainable city is a fine balance.
1Summary 重點摘要
A sustainable city meets its people's needs without wrecking the environment or the future — through greening, mass transit and compact vertical development. Hong Kong's transit-based travel and Singapore's Garden City are models.
2Vocabulary cards Vocabulary
A city balancing environment, economy and society — meeting today's needs without shortchanging the future.
Adding parks, trees, green roofs and living walls to cool the city and soak up carbon.
Singapore's greening policy since the 1960s; green cover now approaches half the island.
High-capacity rail and buses, far more energy-efficient per passenger than cars.
Hong Kong's model of funding railways with property income and growing new towns along the lines.
The quota licence Singaporeans must bid for before owning a car, capping vehicle numbers.
Government-built homes let or sold below market prices, like Hong Kong's PRH and Singapore's HDB flats.
Singapore's public housing by the Housing and Development Board, home to about 80% of the population.
Cities running hotter than their surroundings because concrete traps heat; greening and ventilation corridors ease it.
3Step by step Steps
- Para 1: three pillars of a sustainable cityA sustainable city balances three pillars at once: environment (low-carbon and green), economy (vitality and jobs) and society (fair housing with the vulnerable cared for). To assess whether a city is sustainable, ask three questions — Is the air clean and the city green? Is the economy dynamic? Can ordinary people afford a home? The three answers together form the basic framework of evaluation.
- Para 2: greening and liveabilityGreenery is the most direct indicator of the environmental pillar. Singapore's green cover nears 50%, with park connectors threading the whole island so residents can walk and cycle in the shade; Hong Kong's urban open space is only about 2 square metres per person, well below international norms. Studies show green roofs can cool top-floor flats by some 2 to 3 degrees Celsius, cutting air-conditioning use and easing the urban heat island — a measure worth adopting in dense cities.
- Para 3: mass transit as the backboneTransport is a major source of urban carbon, so public transit forms the backbone of a sustainable city. About 90% of trips in Hong Kong ride public transport, among the world's highest shares; one packed MTR train carries as many people as hundreds of private cars while taking up far less road. Singapore caps private-car growth with COE quotas and concentrates investment in metro and bus networks, with equally clear results.
- Para 4: the compact vertical cityHong Kong grows as a dense vertical city: only about a quarter of its land is built up while country parks cover about 40%, preserving wide natural areas. The 'Rail plus Property' model concentrates new towns such as Tseung Kwan O along railway lines, making travel convenient and infrastructure efficient. The model has costs, though: crowded living, a marked urban heat island and persistently high home prices — strains on the social pillar.
- Para 4: balancing density and quality of lifeHigh density need not mean poor living; design decides. After the 'wall-building' controversy, planning rules added ventilation corridors to major developments so sea breezes reach the streets, while waterfront promenades and town parks give breathing space among the towers. Singapore's HDB towns place parks and hawker centres every few blocks, meeting daily needs on foot — proof that density and liveability can coexist when planning is careful.
- Answer framework: definition plus three pillarsA safe framework for sustainable-city questions: define first, then argue pillar by pillar with examples — Singapore's greening, Hong Kong's public transport and public housing; then name the limits such as cost and crowding; and finish with a conditional verdict. Asked whether Hong Kong is sustainable, affirm transit and density first, then flag weak greening and housing as the gaps.
4Diagrams Diagrams
5Worked example Example
Example: Hong Kong is called a vertical city — what are the pros and cons of this model for sustainability?
- Pro one: land saved — only about a quarter is built up, leaving country parks and farmland intact
- Pro two: energy and emissions — density makes transit efficient; about 90% of trips ride public transport, keeping per-capita transport carbon below most low-density cities
- Pro three: services close by — schools, clinics and markets within walking distance cut long commutes
- Cons: crowding — little space per person and subdivided flats; heat island and wall-like towers baking the streets; towers depend on lifts and air-conditioning, so buildings burn power
- Answer: The vertical city saves land, runs efficient transit and clusters services, but brings crowding, heat and building energy use; the key is topping up with ventilation corridors, greening and public housing to make density liveable. Tip: give three pros and three cons with figures (a quarter built up, 90% transit) and close on sustainability.
6Common mistakes Mistakes
7Quick check Quick check
Q1What are the three pillars of a sustainable city?
Q2What has Singapore's Garden City policy achieved?
Q3How high is Hong Kong's public transport share?
Q4How does Singapore control car growth?
Q5Give two benefits and one drawback of dense development.
8Recap Recap
- Sustainable city: environment, economy and society in balance
- Greening: Singapore's Garden City nears 50% green cover
- Transit: about 90% of Hong Kong trips ride public transport, keeping per-capita carbon low
- Vertical development: about a quarter of Hong Kong is built up; Rail plus Property grows towns along lines
- Density needs complements — ventilation corridors, greening, public housing — or crowding and heat bite back