Megacities

The different patterns of population movement that happen in cities make up the cycle of urbanisation. Cities don't just go through the stages one by one through - different population movements can be happening in a city at the same time.

• Urbanisation
• Suburbanisation
• Counter-urbanisation
• Re-urbanisation

The growth in the proportion of people living in urban cities.

It occurs because of migration - especially rural-urban migration.

Urbanisation is happening quickly in developing countries because of the massive rural-urbam migration. One of the ways the cities have grown is by poor migrants setting up shanty towns - unplanned and often illegal settlements where people build their own homes out of whatever they can find, usually on the outskirts of the city.

The movement of people from the city centre to lower density housing on the outskirts of the city.

As urbanisation increases city centres become overcrowded and people want more space. Improvements to public transport mean people can live further away but still reach the city centre easily.

As megacities grow, more suberbs are added so older suburbs aren't on the outskirts any more.

A complex pattern of wealthy and poorer areas develops. Wealthy people live in suburbs on the outskirts of the city because they can afford more space. Wealthy people also move into poorer suburbs closer to the centre and renovate the houses - this process is called gentrification.

The movement of people out of the city into surrounding villages and rural areas.

Improvements in transport and communications mean people can commute to work or work from home over the internet.

This happens because of high property prices and overcrowding in cities. People may also prefer more quiet rural areas.

The movement of people back into redeveloped city centre residential areas.

In developed countries lots of city centres have been redeveloped. This attracts young, affluent people who want to be near to the cultral activity of the city centre, e.g. redeveloped canal areas such as Brindleyplace and Birmingham.

The London metropolitan area has a population of around 13 million people. 

Greater London is on the flat land around the mouth of the Thames and has a poulatio density of about 4800 people per sqaure km. 

London's urban cycle:

• Urbanisation is still occuring - people are migrating to Greater London from abroad. Almost all parts of Greater London gained, but the biggest gains of migrants are in central areas, e.g. Westminster.
• Counter-urbanisation is happening - people are moving out of Greater London to the rest of the UK.
• Reurbanisation has happened around the London Docklands - the area east of central London that used to be a major port. The port moved upriver between 1965 and 1980 and the area was left derelict. It's been redeveloped since the 1980s and the population has more than doubled. 

London has a post-induatrial economy - the economy used to be based on industry and manufacturing, but now it's mostly based on services.

• It's a major financial centre. London has one of the largest stock exchanges in the world. Many global banks have their headquaters in the centre of London, e.g. HSBC.
• Tourism is a major part of the economy. London is one of the most popular cities to visit in the world, e.g. it attracted more than 15 million foreign tourists in 2006.

London has a complex residential pattern that includes contrasting rich and poor areas.

• Parts of poorer areas in the east of inner London, e.g. Hackney, have been changed because of gentrification. Richer people have moved in, making a mixed pattern of rich and poor people living near to each other.
• Suburban growth has meant villages around London grew in the 19th century . Other suburbs have grown around it. Wealthy people still live there, but it's also a destination for poorer immigrants.

Mumbai is a megacity on the west coast of India.

The Mumbai metropolitan area has a population of more than 20 million people. 

Greater Mumbai is on an island seperated from the mainland by the river Ulhas. It has a high population density - more than 20000 people per square km.

The urban cycle of Mumbai:

The population of Mumbai is growing rapidly.

• Massive uranisation is occuring - people are  migrating to Mumbai from all over India,.
• Suburbanisation is occuring - some people are moving north, away from the inner city on the southern tip of the island. Suburbs are being uilt along the main rail and road routes out of the city,

Mumbai has a fast growing economy based on manufacturing, but the service industry is becoming more important:

• Until the 1980s, the economy was based on textiles manufacturing and shipping.
• There's been an increase in IT and financial services recently.
• Mumbai's a major centre of out-sourcing - companies in Mumbai work for foreign companies.
• Mumbai is a major media centre for India, e.g. Bollywood. It's one of the largest film industries in the world

The residentail pattern of Greater Mumbaiis complex:

• The wealthiest area is enar to the CBD.
• Around half of the population of Greater Mumbai live in shanty towns. They're squeezed in wherever there's space, e.g. Dharavi is the biggest shanty town (over 600 000 people live there) - it's next to the CBD.
• Wealthier suburbs have been built along the road and rail routes that run north out of the CBD, but shanty towns are also squeezed in as near to the transport links as possible. 

Flows of trade, money, people and cluture link London and Mumbai together, accelerating globalisation. For example:

• Cadbury has its global headquaters in London, and its subsidary company, Cadbury India, has its main office in Greater Mumbai. There are flows of trade, money, information and people between the two parts of the same company.
• There are close links between the film industries in London and Mumbai, e.g. in 2006 more than 40 Bollywood films were made in London. This means there's a flow of trade and oney as well as culture between the two cities.