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Our increasing global population is close to reaching 8 billion! Over half of these people live in a city! Perhaps you live in a city, or you have previously lived in a city. Even if this is not the case, you’ve likely visited a city. But what about a megacity? What is the definition of a megacity? What are their characteristics? And what are some opportunities and problems within megacities?

Megacities definition

Megacities are key in today’s society. In fact, around 60% of the world's population lives in a megacity. They play a large role in economies, not only regional economies but also global economies. Although, there are some social and environmental challenges alongside megacities.

Megacities New York City skyline StudySmarterFig. 1 - An example of a megacity is New York City.

Firstly, it is critical to distinguish the difference between megacities from millionaire cities, meta cities, and world cities.

City typeDefinition
MegacityA population of over 10 million.
Millionaire cityA population of 1 million.
MetacityA population of around 20 million.
World cityImportant global cities that are key in the economic system, irrelevant of their population size.
Table 1

New York City is also a world city!

Characteristics of megacities

The characteristics are the various features that constitute megacities. But what are these major characteristics?


The first major characteristic of megacities is their population size. Megacities have populations of over 10 million. They are ultimately large, urban agglomerations.

Large surface area

Another factor that characterises megacities is their vast surface area. Despite covering a large region, megacities are usually densely populated metropolitan areas that can be found all over the world from Asia, Africa, the Americas, and even the United Kingdom.

Extensive transport system

Transportation is another key element of megacities; many megacities contain multiple methods of transportation. People navigate their way around a megacity by walking, cycling, driving, and using buses, trams and trains, such as metro systems. This is due to the fact the demand for these methods of transportation is so high since the populations of megacities are so large.

The London Underground is a good example. It is a large, extensive system of trains that people use to navigate their way around the megacity.

Megacities in the world

The first megacities in the world were Tokyo and New York City in the 1950s. However, this rapidly changed, and by 2018, the United Nations stated there were 28 megacities across the world. There are currently approximately 34 megacities in the world. Yet, this number is expected to continue to increase due to the huge, continuous advancement of urbanisation and population growth.

Occasionally, you may find the population size for the same city may differ depending on what source you are using. This is because researchers define city boundaries differently. One researcher may include suburban areas in their measure of a city’s population size, whereas another researcher may stick to the city’s boundaries.

This rapid growth in megacities is due to the range of opportunities provided by megacities, which will be examined later in this explanation. First, let's take a look at some examples.

Examples of megacities

Many megacities can be found all over the world and in both high-income countries (HICs) and low-income countries (LICs.) Below is a list of some of these megacities.

  • Shenzhen, China – population of around 12 million.
  • Delhi, India – population of around 32 million.
  • Manila, Philippines – population of around 14 million.
  • Mexico City, Mexico – population of around 22 million.
  • Seoul, South Korea – population of around 10 million.
  • London, UK – population of around 10 million.


The largest megacity in the world is Tokyo in Japan. The metropolis currently has an estimated population of over 30 million; however, the direct city has an estimated population of 14 million people.

Megacities Tokyo skyline StudySmarterFig. 2 - Tokyo.

Tokyo has been considered a megacity since the 1950s, making it one of the first-ever megacities. Tokyo is the capital of Japan, allowing it to have various global connections, and therefore economic gain, as well as an excellent transport system. All of these factors make it a suitable megacity.

Opportunities in megacities

As stated earlier, the number of megacities worldwide is seeing a continued increase. This is due to the many opportunities that megacities provide. Let's take a look.


Rural-to-urban migration is common. People are migrating out of rural areas and into urban areas such as megacities due to a range of push-pull factors. The table below shows the push-pull factors of migration to megacities.

FactorPush factors (away from rural regions)Pull factors (towards megacities)
Working opportunitiesThere is a decreasing number of working opportunities in rural regions.Megacities offer a range of working opportunities due to the large number of businesses located in megacities. This provides the opportunity for better pay, career development and therefore higher individual wealth.
AgricultureDue to technological advancement, agricultural efficiency is higher than ever. This means fewer people are required to work in rural agriculture, which displaces many farm workers.There is a high demand for labour jobs such as factories in megacities.
InfrastructureLess infrastructure and often at a lower quality than megacity infrastructure.The quality of infrastructure is higher in megacities, making transportation easier and at a fairly cheap price.
Goods and servicesLimited availability of goods and services.A wide range of goods and services are readily available, including high-quality health care and education in megacities.
InvestmentLess investment into rural areas. More investment into megacities because of the economic benefits as well as the high and dense populations.
Recreation activitiesLess recreational activities are available.High range of various recreational activities in megacities.
FreedomMore traditional values are upheld that may be strict.Higher acceptance of views on politics and religion.
Table 2


Production is another opportunity presented by megacities. The high population numbers of megacities allow for high levels of productivity, which generates economic advancement. Companies recognise the production opportunities of megacities, placing their research and development teams in HIC megacities and their manufacturing teams in LIC megacities. This allows companies to grow and increase economic revenue.

The globalisation of the economy

There is also a major economic profit from megacities. Megacities have considerable connections worldwide. This allows a more streamlined flow of business universally, which enriches the global economy.


Megacities are often huge political hubs. Political decisions can be made in megacities as they hold influence and power due to their high population size.

Problems with megacities

Although megacities offer these advantages, there are also issues associated with megacities. The main elements of these problems are environmental and social factors.

Environmental problems

Environmental issues caused by megacities are likely to increase in the coming years.

Ecological footprint

Megacities have massive ecological footprints. Since megacities have such giant populations, energy demand and therefore energy use is particularly high. High levels of waste are also generated in megacities. This produces a large ecological footprint, which is a measure of human demand and its impact on the environment.


Megacities are giant polluters. This is because of their urban setting. Various transportation and work environments, such as industrial practices and energy demand, release high levels of pollutants such as carbon dioxide. Not only do these reduce the air quality of the location, but they also contribute to global warming through greenhouse gas emissions. Consequently, this contributes to climate change.

Social problems

Megacities are home to millions of people, which makes social problems more likely.

Urban sprawl

Urban sprawl is the accelerated expansion of urban areas. This uncontrolled growth occurs in megacities and can lead to issues such as overcrowding and congestion. Due to the various transportation methods in megacities, congestion can become a major issue in megacities, disrupting traffic flows and causing accidents.


Megacities, typically acquire high levels of inequality associated with housing, employment, water availability and sanitation.


Housing availability is an issue in megacities. The rapid growth of megacities increases the demand for housing, which cannot necessarily always be met. This leads to squatting, homelessness, and slum areas.

Megacities Slums on a hillside StudySmarterFig. 3 - Slum area in a megacity.

Slums are densely populated urban areas. They are impoverished areas, that contain weak buildings, often built by their inhabitants.

Slums are usually found in the developing world and experience high levels of poverty.


Although employment opportunities are a pull factor for megacities, the rapid growth of megacities means that the number of jobs cannot keep up with the growing population of the megacity. This leaves people without employment. However, there is an opportunity for informal employment in megacities, which includes unskilled labour. Unfortunately, this allows low wages and poor treatment of staff.

Water availability and sanitation

Water availability and sanitation can become an issue in megacities. Due to the high demand for megacities, ensuring access to water for everyone in a megacity is particularly difficult, especially in slum areas. This can cause people to pick up water bourne diseases from poor-quality water.

Megacities - Key takeaways

  • Megacities are cities with a population of over 10 million.
  • Characteristics of megacities include population, large surface areas, and extensive transport systems.
  • A good example of a megacity is Tokyo in Japan, which has a metropolis population of around 32 million.
  • Opportunities for megacities include migration, production, global economies, and governance.
  • Problems of megacities include environmental issues such as ecological footprints and pollution. And social issues, such as urban sprawl, inequality, housing, employment, water availability, and sanitation.


  1. Fig 1. An example of a megacity: is New York City. (https://commons.wikimedia.org/wiki/File:EmpireStateNewYokCity.jpg) by Sam valadi (https://www.flickr.com/photos/132084522@N05/17178926219/in/photostream/) licensed by CC BY-SA 2.0 (https://creativecommons.org/licenses/by/2.0/deed.en).
  2. Fig 2. Tokyo (https://commons.wikimedia.org/wiki/File:Tokyo_skyline_seen_from_Tokyo_Skytree.jpg) by Ruthsic (https://commons.wikimedia.org/w/index.php?title=User:Ruthsic&action=edit&redlink=1) licensed by CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/deed.en).
  3. Fig 3. Slum area in a megacity (https://commons.wikimedia.org/wiki/File:Favela_da_rocinha_panorama,_rio_de_janeiro,_brazil_2006_(4538075878).jpg) by seiser+seiser (https://www.flickr.com/people/94852245@N00) licensed by CC BY-SA 2.0).

Frequently Asked Questions about Megacities

Most megacities are located in Asia. China has around 10 megacities.

There are an estimated 34 megacities.

Megacities are cities with a population of at least 10 million.

The future of megacities includes the increasing size and number of megacities worldwide.

There is expected to be 39 megacities by 2030, making the number even higher by 2050.

Megacities are important because of their global economic connections. They also impact social and political dynamics globally.

Final Megacities Quiz


What is a megacity?

Show answer


A city with a population of over 10 million.

Show question


Which of these cities are considered megacities?

Show answer


London, UK.

Show question


What is the estimated population of Tokyo's metro area in Japan?

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32 million.

Show question


List the opportunities of megacities.

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Migration, production, global economies, and governance.

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List the challenges of megacities.

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Ecological footprints, pollution, urban sprawl, inequality, housing, employment, and water availability and sanitation.

Show question


True or false? A pull factor of megacities include megacities lack of recreational activities offered.

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Show question


Fill in the blank. Governance is an opportunity in megacities due to ____ decisions can be made in megacities because they are great political hubs.

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Show question


Fill in the blanks. Megacities have a ____ surface area and ____ population.

Show answer


Large, dense.

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Why is housing an issue in megaicties?

Show answer


The high demand for housing in megacities due to their large growth and high levels of migration cannot be met, which leads to levels of homelessness, squatting, and slum areas.

Show question


What are the main characteristics of megacities?

Show answer


Population size, large surface area and high density, and extensive transport systems.

Show question


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