A megacity is generally defined as a metropolitan area with a total population in excess of 10 million people. Some definitions also set a minimum level for population density (at least 2,000 persons/square km). Megacities can be distinguished from global cities by their rapid growth, new forms of spatial density of population, formal and informal economics, as well as poverty, crime, and high levels of social fragmentation. A megacity can be a single metropolitan area or two or more metropolitan areas that converge upon one another. The terms conurbation and metroplex are also applied to the latter. The terms megapolis and megalopolis are sometimes used synonymously with megacity.

In 1800 only 3% of the world's population lived in cities. 47% did by the end of the twentieth century. In 1950, there were 83 cities with populations exceeding one million; but by 2007, this had risen to 468 agglomerations of more than one million. If the trend continues, the world's urban population will double every 38 years, say researchers. The UN forecasts that today's urban population of 3.2 billion will rise to nearly 5 billion by 2030, when three out of five people will live in cities.

The increase will be most dramatic in the poorest and least-urbanised continents, Asia and Africa. Surveys and projections indicate that all urban growth over the next 25 years will be in developing countries. One billion people, one-sixth of the world's population, now live in shanty towns, which are seen as "breeding grounds" for social problems such as crime, drug addiction, alcoholism, poverty and unemployment. In many poor countries overpopulated slums exhibit high rates of disease due to unsanitary conditions, malnutrition, and lack of basic health care. By 2030, over 2 billion people in the world will be living in slums. Already over 90% of the urban population of Ethiopia, Malawi and Uganda, three of the world's most rural countries, live in slums.

Global connectedness and local disconnectedness characterize megacities. The level of slums contrasts the global capital building capabilities. This can be viewed as one of the tensions brought about by the globalization of modern cities. In 2000, there were 18 megacities – conurbations such as Tokyo, New York City, Los Angeles, Mexico City, Buenos Aires, Mumbai (then Bombay), São Paulo, Karachi that have populations in excess of 10 million inhabitants. Greater Tokyo already has 35 million, which is greater than the entire population of Canada.

By 2025, according to the Far Eastern Economic Review, Asia alone will have at least 10 metacities (cities with a population greater than 20 million), including Jakarta, Indonesia (24.9 million people), Dhaka, Bangladesh (26 million), Karachi, Pakistan (26.5 million), Shanghai (27 million) and Mumbai (33 million). Lagos, Nigeria has grown from 300,000 in 1950 to an estimated 15 million today, and the Nigerian government estimates that the city will have expanded to 25 million residents by 2015. Chinese experts forecast that Chinese cities will contain 800 million people by 2020.

Largest cities

City Growth

In 1950, New York was the only urban area with a population of over 10 million. Geographers have identified 25 such areas as of October 2005, as compared with 19 megacities in 2004 and only nine in 1985. This increase has happened as the world's population moves towards the high (75–85%) urbanization levels of North America and Western Europe. The 1990 census marked the first time the majority of US citizens lived in cities with over 1 million inhabitants.

In the 2000s, the largest megacity is the Greater Tokyo Area. The population of this urban agglomeration includes areas such as Yokohama and Kawasaki, and is estimated to be between 35 and 36 million. This variation in estimates can be accounted for by different definitions of what the area encompasses. While the prefectures of Tokyo, Chiba, Kanagawa, and Saitama are commonly included in statistical information, the Japan Statistics Bureau only includes the area within 50 kilometers of the Tokyo Metropolitan Government Offices in Shinjuku, thus arriving at a smaller population estimate. A characteristic issue of megacities is the difficulty in defining their outer limits and accurately estimating the population.

The ten largest megacities, according to this criterion are:

Rank Megacity Country Population
1 Tokyo Japan 33,600,000
2 Seoul South Korea 23,400,000
3 Mexico City Mexico 22,400,000
4 New York City USA 21,961,994
5 Mumbai (Bombay) India 21,600,000
6 Delhi India 21,500,000
7 São Paulo Brazil 20,600,000
8 Los Angeles USA 18,000,000
9 Shanghai China 17,500,000
10 Osaka Japan 16,700,000
Source: Th. Brinkhoff: The Principal Agglomerations of the World, 2006-11-22

Other megacities include:

Rank Megacity Country Population
11 Cairo Egypt 16,100,000
12 Buenos Aires Argentina 16,000,000
13 Kolkata India 15,700,000
14 Metro Manila Philippines 15,600,000
15 Jakarta Indonesia 15,100,000
15 Karachi Pakistan 15,100,000
16 Tehran Iran 13,500,000
17 Beijing China 12,800,000
18 Dhaka Bangladesh 12,750,000
19 Lahore Pakistan 12,700,000
20 London United Kingdom 12,500,000
21 Paris France 12,000,000
22 Istanbul Turkey 11,800,000
23 Rio de Janeiro Brazil 11,500,000
24 Lagos Nigeria 10,200,000
25 Moscow Russia 10,100,000
25 Bangkok Thailand 10,100,000

Another list defines megacities as urban agglomerations instead of metropolitan areas. As of 2007, there are 22 megacities by this definition.

Emerging Megacities

United Nations projections indicate a steady downturn in the emergence of new megacities after 2005. However, the expansion and merging of highly-urbanized zones (megalopolises) may remain an important trend, as typified by the following:

Emerging megacities in China (in decreasing order of population):

Emerging megacities in India (in decreasing order of population):

Emerging megacities in Pakistan (in decreasing order of population):


The city is not a concrete jungle. It's a human zoo.
Desmond Morris

The world’s population of “slum” dwellers increases by 25 million every year. The majority of these numbers come from the fringes of urban margins, located in legal and illegal settlements with insufficient housing and sanitation. This has been caused by the massive migration, both internal and transnational, into cities. This has caused growth rates of urban populations and spatial concentrations not seen before in history. These issues raise problems in the political, social, and economic arenas. The record-setting populations living in urban slums have little or no access to education, healthcare, or the urban economy.


Another list also defines megacities as urban agglomerations (continuous urbanization). Currently (2007), the agglomerations of more than 10,000,000 inhabitants are as follows:
Rank Agglomeration name Country Population
1 Tokyo 25,600,000
2 Seoul 24,400,000
3 Mexico City 22,400,000
4 New York City 21,900,000
5 Mumbai 21,600,000
6 Delhi 21,500,000
7 São Paulo 20,600,000
8 Los Angeles 18,000,000
9 Shanghai 17,500,000
10 Osaka 16,700,000
11 Cairo 16,100,000
12 Kolkata 15,700,000
13 Metro Manila 15,600,000
14 Jakarta 15,100,000
15 Karachi 15,100,000
16 Guangzhou 14,700,000
17 Buenos Aires 13,600,000
18 Moscow 13,500,000
19 Tehran 13,400,000
20 Beijing 12,800,000
21 Dhaka 12,600,000
22 Rio de Janeiro 12,300,000
23 London 12,000,000
24 Istanbul 11,800,000
25 Lagos 10,100,000
26 Paris 10,000,000
Source: City Population

Regional uses of Megacity


In Canada, the 1990s saw the forced amalgamation of several municipal entities in the provinces of Nova Scotia, Ontario and Quebec into larger new municipalities. The process created what was labelled a megacity by the media, although none of the created municipalities fit in the definition of a megacity in the international sense and some of them have less than a million inhabitants.

Examples of megacities in Canada include:

  • Halifax - the cities of Halifax and Dartmouth and surrounding municipalities were merged in 1996 into the Halifax Regional Municipality, often called a "megacity," with a total population under 400,000.
  • Calgary-Edmonton Corridor - It is the one of the most urbanized and densest in Canada and the fastest growing regions in the country due to the recently surging wealth of oil. Six of the 25 fastest growing municipalities in Canada are within this region. The area has over 2.6 million people.
  • Toronto - In 1998 the municipalities that constituted the Municipality of Metropolitan Toronto were merged into a new City of Toronto, currently the largest of the Canadian cities, with a population of 2,503,281 in 2006. The Greater Toronto Area (or GTA) had a population of 5,555,912 in 2006.
  • Kawartha Lakes, Ontario - the primarily rural Victoria County had its townships, towns and villages merged into a "megacity" in 2000. The area has a population of only 70,000 (several thousand less than nearby city of Peterborough) yet takes up an area of 3,059.22 km² giving it a density of only a mere 22.6 persons per km².
  • Ottawa - the municipalities that constituted the Regional Municipality of Ottawa-Carleton were merged into a new City of Ottawa in 2001.
  • Gatineau - five municipalities in southwestern Quebec (Gatineau, Hull, Aylmer, Buckingham, and Masson-Angers) were merged into a new City of Gatineau in 2002.
  • Montreal - all of the municipalities on the island of Montreal were merged into a new City of Montreal for a short period of time until January 1, 2006, when a partial demerger occurred.
  • Greater Sudbury - resulted from the merger of the former Regional Municipality of Sudbury in 2001.
  • Hamilton - the municipalities that constituted Hamilton-Wentworth merged in a new City of Hamilton in 2001.

For more information on Ontario "megacities," see the article on the Common Sense Revolution.

In fiction

  • Fictional megacities feature in much dystopian science fiction, with examples such as the Sprawl, featured in William Gibson's Neuromancer, and Mega-City One, a megalopolis of over 400 million people across the east coast of the United States, features in the Judge Dredd comic, serialised in 2000 AD. Demolition Man (1993) features a megacity called "San Angeles", formed from the joining of Los Angeles, Santa Barbara, San Diego, and the surrounding metropolitan regions following a massive earthquake.
  • Soylent Green (1973) depicted New York City in 2022 with a population of 40 million. The city has a huge food shortage, which leads one company, the manufacturers of the popular food "Soylent Green" to create food out of the deceased, telling customers that it is plankton. It is not said how large the city is, but the main character does make the comment that something is "over the city line in Philadelphia" making the viewer wonder if the city has sprawled that far.
  • Planet-wide megacities (ecumenopoleis) have been depicted, including Trantor in Isaac Asimov's Foundation series of books, Coruscant in the Star Wars universe, 'City Europe' in David Wingrove's Chung Kuo series of books, Holy Terra and the hive cities of Necromunda in Warhammer 40,000, and Ravnica in the eponymous Magic: The Gathering expansion. In Stargate Atlantis, the Asurans appear to have an extremely large city that may or may not be an ecumenopolis, named Asuras.
  • Many of these fictional depictions were inspired by Fritz Lang's 1927 film, Metropolis. Ridley Scott's 1982 film, Blade Runner, features an influential depiction of Los Angeles in 2019. The MMORPG game "Guild Wars" has a massive, fictional megacity on its southern continent, Cantha, called Kaineng City which is very run down, corrupted, and in colossal slums and poverty. The city is a daily struggle for survival infested with crime, plagues, starvation, and a massive sewer system called the "undercity".
  • Another MMORPG game City of Heroes is set in the fictional megacity known as Paragon City, which contains two other cities: Galaxy City and Skyway City. In the two novels based on the game as well as the official timeline for the game, Paragon City has existed at least as far back as the early to mid-1800s. Paragon is depicted as being one of if not the single largest city on Earth in its world setting. The sprawling metropolis featured in The Matrix series of films can be considered a megacity. While the city is never referenced by name in the films, in the MMORPG The Matrix Online, the city itself is simply called the Mega City. The city is based on Sydney, Chicago, and Oakland, California.
  • The Fifth Element has a parody of New York City set in 2263 which is completely built up with depleted water levels the city is transformed into a much bigger metropolis than it is today. Buildings are so high that people use flying cars to get around and the ground level of the Earth is obscured by cloud cover.

See also


Soja, Edward W., "Postmetropolis, Critical Studies of Cities and Regions", Blackwell Publishing Ltd., 2000 (alk. paper, ISBN 1-55718-000-3; paperback, ISBN 1-55718-001-1)

External links

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