A megacity is a very large
city
A city is a human settlement of notable size.Goodall, B. (1987) ''The Penguin Dictionary of Human Geography''. London: Penguin.Kuper, A. and Kuper, J., eds (1996) ''The Social Science Encyclopedia''. 2nd edition. London: Routledge. It can be def ...
, typically with a
population
Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a ...
of more than 10 million people. Precise definitions vary: the
United Nations Department of Economic and Social Affairs
The United Nations Department of Economic and Social Affairs (UN DESA) is part of the United Nations Secretariat and is responsible for the follow-up to major United Nations Summits and Conferences, as well as services to the United Nations Econ ...
in its 2018 "World Urbanization Prospects" report counted
urban agglomeration
An urban area, built-up area or urban agglomeration is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities, t ...
s having over 10 million inhabitants.
A
University of Bonn
The Rhenish Friedrich Wilhelm University of Bonn (german: Rheinische Friedrich-Wilhelms-Universität Bonn) is a public research university located in Bonn, North Rhine-Westphalia, Germany. It was founded in its present form as the ( en, Rhine U ...
report held that they are "usually defined as
metropolitan area
A metropolitan area or metro is a region that consists of a densely populated urban agglomeration and its surrounding territories sharing industries, commercial areas, transport network, infrastructures and housing. A metro area usually com ...
s with a total population of 10 million or more people". Others list cities satisfying criteria of either 5 or 8 million and also having a population density of 2,000 per square kilometre.
The terms
conurbation
A conurbation is a region comprising a number of metropolises, cities, large towns, and other urban areas which through population growth and physical expansion, have merged to form one continuous urban or industrially developed area. In most ca ...
,
metropolis
A metropolis () is a large city or conurbation which is a significant economic, political, and cultural center for a country or region, and an important hub for regional or international connections, commerce, and communications.
A big c ...
, and metroplex are also applied to the latter.
[
The total number of megacities in the world varies between different sources: The world had 33 according to the UN (in 2018), 37 according to ''CityPopulation.de'' (in 2020), and 35 according to '']Demographia
Wendell Cox is an American urban policy analyst and proponent of the use of the private car over rail projects. He is the principal and sole owner of Wendell Cox Consultancy/Demographia, based in the St. Louis metropolitan region and editor of thre ...
'' (in 2020). About half these urban agglomerations are in China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
and India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
. The other four countries with more than one megacity are Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
, Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
, Pakistan
Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
, and the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
. African megacities are present in Nigeria
Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...
, Egypt
Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...
, South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...
, and the DRC
The Democratic Republic of the Congo (french: République démocratique du Congo (RDC), colloquially "La RDC" ), informally Congo-Kinshasa, DR Congo, the DRC, the DROC, or the Congo, and formerly and also colloquially Zaire, is a country in ...
; European megacities are present in Russia
Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...
, France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
, the United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and North ...
, and Turkey
Turkey ( tr, Türkiye ), officially the Republic of Türkiye ( tr, Türkiye Cumhuriyeti, links=no ), is a list of transcontinental countries, transcontinental country located mainly on the Anatolia, Anatolian Peninsula in Western Asia, with ...
(also in Asia); megacities can be found in Latin America in the countries of Brazil, Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
, Colombia
Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...
, Peru
, image_flag = Flag of Peru.svg
, image_coat = Escudo nacional del Perú.svg
, other_symbol = Great Seal of the State
, other_symbol_type = Seal (emblem), National seal
, national_motto = "Fi ...
, and Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
. Some sources identify Tokyo's Greater Tokyo Area
The Greater Tokyo Area is the most populous metropolitan area in the world, consisting of the Kantō region of Japan (including Tokyo Metropolis and the prefectures of Chiba, Gunma, Ibaraki, Kanagawa, Saitama, and Tochigi) as well as the ...
as the largest megacity in the world, while some others give the title to Pearl River Delta
The Pearl River Delta Metropolitan Region (PRD; ; pt, Delta do Rio das Pérolas (DRP)) is the low-lying area surrounding the Pearl River estuary, where the Pearl River flows into the South China Sea. Referred to as the Guangdong-Hong Kong-Mac ...
.
List of megacities
History
The term "megacity" entered common use in the late 19th or early 20th centuries; one of the earliest documented uses of the term was by the University of Texas
The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas. It was founded in 1883 and is the oldest institution in the University of Texas System. With 40,916 undergraduate students, 11,075 ...
in 1904. Initially the United Nations
The United Nations (UN) is an intergovernmental organization whose stated purposes are to maintain international peace and international security, security, develop friendly relations among nations, achieve international cooperation, and be ...
used the term to describe cities of 8 million or more inhabitants, but now uses the threshold of 10 million. In the mid 1970s the term was coined by urbanist Janise Perlman referring to the phenomenon of very large urban agglomerations.
In 1800, only 3% of the world's population lived in cities, a figure that rose to 47% by the end of the twentieth century. In 1950, there were 83 cities with populations exceeding one million; by 2007, this number had risen to 468. 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, or sixty percent, of people will live in cities.
This increase will be most dramatic on the least-urbanized continents, Asia
Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...
and Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
. Surveys and projections indicate that all urban growth over the next 25 years will be in developing countries
A developing country is a sovereign state with a lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreem ...
. One billion people, almost one-seventh of the world's population, now live in shanty towns. In many poor countries, overcrowded slums exhibit high rates of disease
A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...
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
A slum is a highly populated urban residential area consisting of densely packed housing units of weak build quality and often associated with poverty. The infrastructure in slums is often deteriorated or incomplete, and they are primarily in ...
. Over 90% of the urban population of Ethiopia
Ethiopia, , om, Itiyoophiyaa, so, Itoobiya, ti, ኢትዮጵያ, Ítiyop'iya, aa, Itiyoppiya officially the Federal Democratic Republic of Ethiopia, is a landlocked country in the Horn of Africa. It shares borders with Eritrea to the ...
, Malawi
Malawi (; or aláwi Tumbuka: ''Malaŵi''), officially the Republic of Malawi, is a landlocked country in Southeastern Africa that was formerly known as Nyasaland. It is bordered by Zambia to the west, Tanzania to the north and northeast ...
and Uganda
}), is a landlocked country in East Africa
East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territor ...
, three of the world's most rural countries, already live in slums.
By 2025, Asia alone will have at least 30 megacities, including Mumbai
Mumbai (, ; also known as Bombay — the official name until 1995) is the capital city of the Indian state of Maharashtra and the ''de facto'' financial centre of India. According to the United Nations, as of 2018, Mumbai is the second- ...
, India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
(2015 population of 20.75 million people), Shanghai
Shanghai (; , , Standard Mandarin pronunciation: ) is one of the four direct-administered municipalities of the People's Republic of China (PRC). The city is located on the southern estuary of the Yangtze River, with the Huangpu River flow ...
, China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
(2015 population of 35.5 million people), Delhi
Delhi, officially the National Capital Territory (NCT) of Delhi, is a city and a union territory of India containing New Delhi, the capital of India. Straddling the Yamuna river, primarily its western or right bank, Delhi shares borders w ...
, India (2015 population of 21.8 million people), Tokyo
Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...
, Japan
Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...
(2015 population of 38.8 million people) and Seoul
Seoul (; ; ), officially known as the Seoul Special City, is the capital and largest metropolis of South Korea.Before 1972, Seoul was the ''de jure'' capital of the Democratic People's Republic of Korea (North Korea) as stated iArticle 103 ...
, South Korea
South Korea, officially the Republic of Korea (ROK), is a country in East Asia, constituting the southern part of the Korea, Korean Peninsula and sharing a Korean Demilitarized Zone, land border with North Korea. Its western border is formed ...
(2015 population of 25.6 million people). In Africa, Lagos
Lagos (Nigerian English: ; ) is the largest city in Nigeria and the List of cities in Africa by population, second most populous city in Africa, with a population of 15.4 million as of 2015 within the city proper. Lagos was the national ca ...
, Nigeria
Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...
has grown from 300,000 in 1950 to an estimated 21 million today.
Growth
For almost five hundred years, Rome
, established_title = Founded
, established_date = 753 BC
, founder = King Romulus (legendary)
, image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg
, map_caption ...
was the largest, wealthiest, and most politically important city in Europe. Its population passed one million people by the end of the 1st century BC. Rome's population started declining in 402 AD when Flavius Honorius
Honorius (9 September 384 – 15 August 423) was Roman emperor from 393 to 423. He was the younger son of emperor Theodosius I and his first wife Aelia Flaccilla. After the death of Theodosius, Honorius ruled the western half of the empire whil ...
, Western Roman Emperor from 395 to 423, moved the government to Ravenna
Ravenna ( , , also ; rgn, Ravèna) is the capital city of the Province of Ravenna, in the Emilia-Romagna region of Northern Italy. It was the capital city of the Western Roman Empire from 408 until its collapse in 476. It then served as the cap ...
and Rome's population declined to a mere 20,000 during the Early Middle Ages
The Early Middle Ages (or early medieval period), sometimes controversially referred to as the Dark Ages, is typically regarded by historians as lasting from the late 5th or early 6th century to the 10th century. They marked the start of the Mi ...
, reducing the sprawling city to groups of inhabited buildings interspersed among large areas of ruins and vegetation.
Baghdad
Baghdad (; ar, بَغْدَاد , ) is the capital of Iraq and the second-largest city in the Arab world after Cairo. It is located on the Tigris near the ruins of the ancient city of Babylon and the Sassanid Persian capital of Ctesiphon ...
was likely the largest city in the world from shortly after its foundation in 762 AD until the 930s, with some estimates putting its population at over one million. Chinese capital cities Chang'an
Chang'an (; ) is the traditional name of Xi'an. The site had been settled since Neolithic times, during which the Yangshao culture was established in Banpo, in the city's suburbs. Furthermore, in the northern vicinity of modern Xi'an, Qin Shi ...
and Kaifeng
Kaifeng () is a prefecture-level city in east-central Henan province, China. It is one of the Eight Ancient Capitals of China, having been the capital eight times in history, and is best known for having been the Chinese capital during the Nort ...
also experienced huge population booms during prosperous empires. According to the census in the year 742 recorded in the ''New Book of Tang
The ''New Book of Tang'', generally translated as the "New History of the Tang" or "New Tang History", is a work of official history covering the Tang dynasty in ten volumes and 225 chapters. The work was compiled by a team of scholars of the So ...
'', 362,921 families with 1,960,188 persons were counted in Jingzhao Fu (京兆府), the metropolitan area
A metropolitan area or metro is a region that consists of a densely populated urban agglomeration and its surrounding territories sharing industries, commercial areas, transport network, infrastructures and housing. A metro area usually com ...
including small cities in the vicinity of Chang'an. The medieval settlement surrounding Angkor
Angkor ( km, អង្គរ , 'Capital city'), also known as Yasodharapura ( km, យសោធរបុរៈ; sa, यशोधरपुर),Headly, Robert K.; Chhor, Kylin; Lim, Lam Kheng; Kheang, Lim Hak; Chun, Chen. 1977. ''Cambodian-Engl ...
, the one-time capital of the Khmer Empire which flourished between the 9th and 15th centuries, could have supported a population of up to one million people.
From around 1825 to 1918 London
London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
was the largest city in the world, with the population growing rapidly; it was the first city to reach a population of over 5 million in 1900. In 1950, New York City
New York, often called New York City or NYC, is the List of United States cities by population, most populous city in the United States. With a 2020 population of 8,804,190 distributed over , New York City is also the L ...
was the only urban area with a population of over 10 million. Geographers had 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
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
and Western Europe
Western Europe is the western region of Europe. The region's countries and territories vary depending on context.
The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean ...
.
Since the 2000s, the largest megacity has been the Greater Tokyo Area
The Greater Tokyo Area is the most populous metropolitan area in the world, consisting of the Kantō region of Japan (including Tokyo Metropolis and the prefectures of Chiba, Gunma, Ibaraki, Kanagawa, Saitama, and Tochigi) as well as the ...
. The population of this urban agglomeration
An urban area, built-up area or urban agglomeration is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities, t ...
includes areas such as Yokohama
is the second-largest city in Japan by population and the most populous municipality of Japan. It is the capital city and the most populous city in Kanagawa Prefecture, with a 2020 population of 3.8 million. It lies on Tokyo Bay, south of To ...
and Kawasaki, and is estimated to be between 37 and 38 million. This variation in estimates can be accounted for by different definitions of what the area encompasses. While the prefectures of Tokyo
Tokyo (; ja, 東京, , ), officially the Tokyo Metropolis ( ja, 東京都, label=none, ), is the capital and largest city of Japan. Formerly known as Edo, its metropolitan area () is the most populous in the world, with an estimated 37.468 ...
, Chiba
Chiba may refer to:
Places China
* (), town in Jianli County, Jingzhou, Hubei
Japan
* Chiba (city), capital of Chiba Prefecture
** Chiba Station, a train station
* Chiba Prefecture, a sub-national jurisdiction in the Greater Tokyo Area on ...
, Kanagawa
is a Prefectures of Japan, prefecture of Japan located in the Kantō region of Honshu. Kanagawa Prefecture is the List of Japanese prefectures by population, second-most populous prefecture of Japan at 9,221,129 (1 April 2022) and third-dens ...
, 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
is a special ward in Tokyo, Japan. It is a major commercial and administrative centre, housing the northern half of the busiest railway station in the world (Shinjuku Station) and the Tokyo Metropolitan Government Building, the administration ...
, thus arriving at a smaller population estimate. A characteristic issue of megacities is the difficulty in defining their outer limits and accurately estimating the populations.
Another list defines megacities as urban agglomeration
An urban area, built-up area or urban agglomeration is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities, t ...
s instead of metropolitan areas. As of 2021, there are 28 megacities by this definition, like Tokyo. Other sources list Nagoya
is the largest city in the Chūbu region, the fourth-most populous city and third most populous urban area in Japan, with a population of 2.3million in 2020. Located on the Pacific coast in central Honshu, it is the capital and the most pop ...
and the Rhein-Ruhr
The Rhine-Ruhr metropolitan region (german: Metropolregion Rhein-Ruhr) is the largest metropolitan region in Germany, with over ten million inhabitants. A polycentric conurbation with several major urban concentrations, the region cover ...
as megacities.
Challenges
Slums
According to the United Nations, the proportion of urban dwellers living in slum
A slum is a highly populated urban residential area consisting of densely packed housing units of weak build quality and often associated with poverty. The infrastructure in slums is often deteriorated or incomplete, and they are primarily inh ...
s or informal settlements decreased from 47 percent to 37 percent in the developing world
A developing country is a sovereign state with a lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreem ...
between 1990 and 2005. However, due to rising population, the absolute number of slum dwellers is rising. The majority of these are located in informal settlements which often lack sufficient quality housing, sanitation, drainage, water access, and officially recognized addresses. The increase in informal settlement population has been caused by massive migration, both internal and transnational, into cities, which 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. People who live in slums or informal settlements often have minimal or no access to education, healthcare, or the urban economy.
Crime
As with any large concentration of people, there is usually crime. High population densities often result in higher crime rates, as visibly seen in growing megacities such as Karachi
Karachi (; ur, ; ; ) is the most populous city in Pakistan and 12th most populous city in the world, with a population of over 20 million. It is situated at the southern tip of the country along the Arabian Sea coast. It is the former cap ...
, Delhi
Delhi, officially the National Capital Territory (NCT) of Delhi, is a city and a union territory of India containing New Delhi, the capital of India. Straddling the Yamuna river, primarily its western or right bank, Delhi shares borders w ...
, Cairo
Cairo ( ; ar, القاهرة, al-Qāhirah, ) is the capital of Egypt and its largest city, home to 10 million people. It is also part of the largest urban agglomeration in Africa, the Arab world and the Middle East: The Greater Cairo metro ...
, Rio de Janeiro
Rio de Janeiro ( , , ; literally 'River of January'), or simply Rio, is the capital of the state of the same name, Brazil's third-most populous state, and the second-most populous city in Brazil, after São Paulo. Listed by the GaWC as a b ...
, and Lagos
Lagos (Nigerian English: ; ) is the largest city in Nigeria and the List of cities in Africa by population, second most populous city in Africa, with a population of 15.4 million as of 2015 within the city proper. Lagos was the national ca ...
.
Homelessness
Megacities often have significant numbers of homeless
Homelessness or houselessness – also known as a state of being unhoused or unsheltered – is the condition of lacking stable, safe, and adequate housing. People can be categorized as homeless if they are:
* living on the streets, also kn ...
people. The actual legal definition of homelessness varies from country to country, or among different entities or institutions in the same country or region.
In 2002, research showed that children and families were the largest growing segment of the homeless population in the United States, and this has presented new challenges, especially in services, to agencies.
In the US, the government asked many major cities to come up with a ten-year plan to end homelessness. One of the results of this was a "Housing first
Housing First is a policy that offers unconditional, permanent housing as quickly as possible to homeless people, and other supportive services afterward. It was first discussed in the 1990s, and in the following decades became government policy ...
" solution, rather than to have a homeless person remain in an emergency homeless shelter it was thought to be better to quickly get the person permanent housing of some sort and the necessary support services to sustain a new home. But there are many complications with this kind of program and these must be dealt with to make such an initiative work successfully in the middle to long term.[Abel, David]
"For the homeless, keys to a home: Large-scale effort to keep many off street faces hurdles"
Boston Globe, February 24, 2008.PBS
The Public Broadcasting Service (PBS) is an American public broadcasting, public broadcaster and Non-commercial activity, non-commercial, Terrestrial television, free-to-air television network based in Arlington, Virginia. PBS is a publicly fu ...
"Home at Last? – A radical new approach to helping the homeless"
''NOW
Now most commonly refers
to the present time.
Now, NOW, or The Now may also refer to:
Organizations
* Natal Organisation of Women, a South African women's organization
* National Organization for Women, an American feminist organization
* Now ...
'' TV program, December 21, 2007.
Traffic congestion
Traffic congestion
Traffic congestion is a condition in transport that is characterized by slower speeds, longer trip times, and increased vehicular queueing. Traffic congestion on urban road networks has increased substantially since the 1950s. When traffic de ...
is a condition on road networks that occurs as use increases, and is characterized by slower speeds, longer trip times, increased pollution, and increased vehicular queueing
Queue areas are places in which people queue (first-come, first-served) for goods or services. Such a group of people is known as a ''queue'' (British usage) or ''line'' ( American usage), and the people are said to be waiting or standing ''in ...
. The Texas Transportation Institute
The Texas A&M Transportation Institute (TTI) in Bryan/College Station, Texas is a transportation research agency in the United States. The institute was created in 1950, primarily in response to the needs of the Texas Highway Department (now th ...
estimated that, in 2000, the 75 largest metropolitan areas experienced 3.6 billion vehicle-hours of delay, resulting in 5.7 billion U.S. gallons (21.6 billion liters) in wasted fuel and $67.5 billion in lost productivity, or about 0.7% of the nation's GDP
Gross domestic product (GDP) is a monetary measure of the market value of all the final goods and services produced and sold (not resold) in a specific time period by countries. Due to its complex and subjective nature this measure is ofte ...
. It also estimated that the annual cost of congestion for each driver was approximately $1,000 in very large cities and $200 in small cities. Traffic congestion is increasing in major cities and delays are becoming more frequent in smaller cities and rural areas.
Urban sprawl
Urban sprawl
Urban sprawl (also known as suburban sprawl or urban encroachment) is defined as "the spreading of urban developments (such as houses and shopping centers) on undeveloped land near a city." Urban sprawl has been described as the unrestricted growt ...
, also known as suburban sprawl, is a multifaceted concept, which includes the spreading outwards of a city and its suburb
A suburb (more broadly suburban area) is an area within a metropolitan area, which may include commercial and mixed-use, that is primarily a residential area. A suburb can exist either as part of a larger city/urban area or as a separate ...
s to its outskirts to low-density, auto-dependent development on rural land, with associated design features that encourage car dependency
Car dependency is the concept that some city layouts cause cars to be favoured over alternate forms of transportation, such as bicycles, public transit, and walking.
Overview
In many modern cities, automobiles are convenient and sometimes nec ...
.[What is Sprawl?](_blank)
. ''SprawlCity.org''. Retrieved on 2008-02-07. As a result, some critics argue that sprawl has certain disadvantages including longer transport distances to work, high car dependence
Car dependency is the concept that some city layouts cause cars to be favoured over alternate forms of transportation, such as bicycles, public transit, and walking.
Overview
In many modern cities, automobiles are convenient and sometimes nec ...
, inadequate facilities (e.g. health, cultural. etc.) and higher per-person infrastructure costs. Discussions and debates about sprawl are often obfuscated by the ambiguity associated with the phrase. For example, some commentators measure sprawl only with the average number of residential units per acre in a given area. But others associate it with decentralization (spread of population without a well-defined center), discontinuity (leapfrog development), segregation of uses, etc.
Gentrification
Gentrification
Gentrification is the process of changing the character of a neighborhood through the influx of more Wealth, affluent residents and businesses. It is a common and controversial topic in urban politics and urban planning, planning. Gentrification ...
and urban gentrification are terms for the socio-cultural changes in an area as a result of wealthier people buying property in a less prosperous community. As living costs rise, lower-income residents are forced to move out of the community leading to an increase in average income, which in turn makes the area more desirable to other wealthier property or business owners, further pushing the living costs up. This process also tends to lead to a decrease in average family size in the area. This type of population change reduces industrial land use
Land use involves the management and modification of natural environment or wilderness into built environment such as settlements and semi-natural habitats such as arable fields, pastures, and managed woods. Land use by humans has a long h ...
when it is redeveloped for commerce and housing.
Air pollution
Air pollution
Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different types ...
is the introduction into the atmosphere
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...
of chemical
A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wi ...
s, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or damages the natural environment
The natural environment or natural world encompasses all life, living and non-living things occurring nature, naturally, meaning in this case not Artificiality, artificial. The term is most often applied to the Earth or some parts of Earth. Th ...
. Many urban areas have significant problems with smog
Smog, or smoke fog, is a type of intense air pollution. The word "smog" was coined in the early 20th century, and is a portmanteau of the words ''smoke'' and '' fog'' to refer to smoky fog due to its opacity, and odor. The word was then inte ...
, a type of air pollution
Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different types ...
derived from vehicle emissions from internal combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combus ...
s and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine with the primary emissions to form photochemical smog
Smog, or smoke fog, is a type of intense air pollution. The word "smog" was coined in the early 20th century, and is a portmanteau of the words ''smoke'' and ''fog'' to refer to smoky fog due to its opacity, and odor. The word was then inten ...
.
Energy and material resources
The sheer size and complexity of megacities gives rise to enormous social and environmental challenges. Whether megacities can develop sustainably depends to a large extent on how they obtain, share, and manage their energy and material resources. There are correlations between electricity consumption
Electric energy consumption is the form of energy consumption that uses electrical energy. Electric energy consumption is the actual energy demand made on existing electricity supply for transportation, residential, industrial, commercial, and ot ...
, heating and industrial fuel use, ground transportation energy use, water consumption
A water footprint shows the extent of water use in relation to consumption by people. The water footprint of an individual, community, or business is defined as the total volume of fresh water used to produce the goods and services consumed by th ...
, waste generation, and steel production
Steelmaking is the process of producing steel from iron ore and carbon/or scrap. In steelmaking, impurities such as nitrogen, silicon, phosphorus, sulfur and excess carbon (the most important impurity) are removed from the sourced iron, and ...
in terms of level of consumption and how efficiently they use resources.[https://shared.uoit.ca/shared/faculty-sites/sustainability-today/publications/compendium_entries/energy-and-material-flows-of-megacities---chris-kennedy.pdf ]
In fiction
Megacities are a common backdrop in dystopia
A dystopia (from Ancient Greek δυσ- "bad, hard" and τόπος "place"; alternatively cacotopiaCacotopia (from κακός ''kakos'' "bad") was the term used by Jeremy Bentham in his 1818 Plan of Parliamentary Reform (Works, vol. 3, p. 493). ...
n science fiction
Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel unive ...
, with examples such as the Sprawl in William Gibson
William Ford Gibson (born March 17, 1948) is an American-Canadian speculative fiction writer and essayist widely credited with pioneering the science fiction subgenre known as ''cyberpunk''. Beginning his writing career in the late 1970s, his ...
's ''Neuromancer
''Neuromancer'' is a 1984 science fiction novel by American-Canadian writer William Gibson. Considered one of the earliest and best-known works in the cyberpunk genre, it is the only novel to win the Nebula Award, the Philip K. Dick Award, and ...
'', and Mega-City One
Mega-City One is a fictional city that features in the ''Judge Dredd'' comic book series and related media. A post-nuclear megalopolis covering much of what is now the Eastern United States and some of Canada, the city's exact geography depends ...
, a megalopolis of between 50 and 800 million people (fluctuations due to war and disaster) across the east coast of the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, in the ''Judge Dredd
Judge Joseph Dredd is a fictional character created by writer John Wagner and artist Carlos Ezquerra. He first appeared in the second issue of ''2000 AD (comics), 2000 AD'' (1977), which is a British weekly anthology Comic book, comic. He is the ...
'' comic. In '' Demolition Man'' a megacity called "San Angeles
San Angeles is a fictional futuristic concept of Southern California typically configured by U.S. commentators and film producers to include the areas of Los Angeles to San Diego and sometimes even San Bernardino to Riverside. Although Los Angele ...
" was formed from the joining of Los Angeles
Los Angeles ( ; es, Los Ángeles, link=no , ), often referred to by its initials L.A., is the largest city in the state of California and the second most populous city in the United States after New York City, as well as one of the world' ...
, Santa Barbara, San Diego
San Diego ( , ; ) is a city on the Pacific Ocean coast of Southern California located immediately adjacent to the Mexico–United States border. With a 2020 population of 1,386,932, it is the List of United States cities by population, eigh ...
and the surrounding metropolitan regions following a massive earthquake in 2010. Fictional planet-wide megacities ( ecumenopoleis) include Trantor
The Galactic Empire is an interstellar empire featured in Isaac Asimov's ''Robot'', ''Galactic Empire'', and '' Foundation'' series. The Empire is spread across the Milky Way galaxy and consists of almost 25 million planets settled exclusively b ...
in Isaac Asimov
yi, יצחק אזימאװ
, birth_date =
, birth_place = Petrovichi, Russian SFSR
, spouse =
, relatives =
, children = 2
, death_date =
, death_place = Manhattan, New York City, U.S.
, nationality = Russian (1920–1922)Soviet (192 ...
's ''Foundation'' series of books and Coruscant
Coruscant () is an ecumenopolis planet in the fictional ''Star Wars'' universe. Its first appearance was onscreen in the 1997 Special Edition of ''Return of the Jedi'', but was first depicted and mentioned by name in Timothy Zahn's 1991 novel '' ...
(population 2 trillion) in the ''Star Wars
''Star Wars'' is an American epic film, epic space opera multimedia franchise created by George Lucas, which began with the Star Wars (film), eponymous 1977 film and quickly became a worldwide popular culture, pop-culture Cultural impact of S ...
'' universe.
See also
*Economies of agglomeration
One of the major subfields of urban economics, economies of agglomeration (or agglomeration effects) describes, in broad terms, how urban agglomeration occurs in locations where cost savings can naturally arise. Most often discussed in terms of ...
* Global city
*List of largest cities
The United Nations uses three definitions for what constitutes a city, as not all cities in all jurisdictions are classified using the same criteria. Cities may be defined as the cities proper, the extent of their urban area, or their metropo ...
*List of largest cities throughout history
This article lists the largest human settlements in the world (by population) over time, as estimated by historians, from 7000 BC when the largest populated place in the world was a proto-city in the Ancient Near East with a population of about ...
*Megalopolis
A megalopolis () or a supercity, also called a megaregion, is a group of metropolitan areas which are perceived as a continuous urban area through common systems of transport, economy, resources, ecology, and so on. They are integrated enoug ...
*Urban sprawl
Urban sprawl (also known as suburban sprawl or urban encroachment) is defined as "the spreading of urban developments (such as houses and shopping centers) on undeveloped land near a city." Urban sprawl has been described as the unrestricted growt ...
References
{{Authority control
Urban studies and planning terminology
Human habitats
Population
Types of cities
Cyberpunk themes