Megacity

from Wikipedia.org :

A megacity is usually defined as a metropolitan area with a total population in excess of 10 million people.^[1] 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 termsconurbation and metroplex are also applied to the latter. The terms megapolis and megalopolis are sometimes used synonymously with megacity.

Large Cities in 2006

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.^[2] If the trend continues, the world's urban populationwill 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.^[3]

In 1800 only 3% of the In 1800 only 3% of the 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.^[4] One billion people, one-sixth of the world's population, now live in shanty towns,^[5]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.^[6] By 2030, over 2 billion people in the world will be living in slums.^[7] Already over 90% of the urban population of Ethiopia, Malawi and Uganda, three of the world's most rural countries, live in slums.

In 1800 only 3% of the 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 ofCanada.^[8]

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).^[9] 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.^[10] Chinese experts forecast that Chinese cities will contain 800 million people by 2020.[11]

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