Megacity growth (DP IB Geography): Revision Note
Consequences of Megacity Growth
- Not only is the world more urban, but the urban area is increasing 
- Many cities are sprawling into and engulfing rural regions. This creates conurbations and adds to the growth of urban areas 
- As the growth of cities continues, the term megacity is used to describe cities with more than 10 million people - New York was the first megacity in 1950, with Tokyo 2nd 
- In 1975 there were 4 - New York, Tokyo, Osaka and Mexico City 
- By 2000 there were 15 
- In 2018 that rose to 33 with Tokyo having close to 37.3 million people 
- By 2025-2030, an estimated 630 million people will live in close to 43 megacities around the world 
- Asia alone, has at least 33 megacities, including Mumbai and Delhi, India; Shanghai, China; Seoul, South Korea and Lagos in Nigeria 
 
- This scaling up of the urban environment is the fastest in human history 
- Largest growth of megacities is in Asia 
Distribution of megacities in 2022

Consequences of megacity growth
- Economic development - Megacities dominate the national and regional economies of countries 
- Many companies have their headquarters in megacities 
- Encourages population growth which leads to the desirability of goods and services 
- All megacities act as service centres within the formal economic sector 
- However, megacities in MICs are also important manufacturing centres (Mumbai in India or Dhaka in Bangladesh) with thousands working in the informal economy 
 
- Population growth - Young people are drawn to live in megacities with their vibrancy, fast pace and opportunities 
- There is also ‘internal growth’ where people who have moved into the cities have children, so sustaining population growth (Mexico City, Mumbai, Pearl River Delta in China) 
- Rapid growth, often means that peri-urban, grow more rapidly than urban centres and this can lead to the development of squatter settlements 
 
- Economies of scale - Cheaper to provide goods and services in one place than spread across several cities 
- Financial savings for local governments in respect of infrastructure provision 
- Communication and transport are centralised, making savings in time and money 
- Availability of skilled and unskilled workers (higher numbers allows for choice) 
 
- Multiplier effect - As a city prospers, it acts as a beacon to people and businesses 
- This encourages inward investment 
- This leads to yet more development and growth 
- Generating further need for skills and labour and job growth 
- This cycle multiplies the positive effects and growth continues (San Francisco and the digital development) 
 
Overview of Positive and Negative Impacts of Megacity Growth
| 
 | Positive | Negative | 
|---|---|---|
| Individuals | Improved education Higher wages Better employment opportunities Young, vibrant and fast paced | Overcrowding, expensive and inadequate housing (squatter settlements) Degraded water and sanitation  Public and health services overstretched Employee protection limited or non-existent - informal employment or unemployment Fast-paced environment, noise and pollution can impact mental health | 
| Society | Cultural diversity Social cohesion Increased economic growth Increased services and infrastructure | Increased property prices and urban sprawl Social challenges - racial animosity, rise in crime rates Congestion and pollution | 
Examiner Tips and Tricks
Remember that HICs have had a slower development of megacities, and longer to accommodate the growth. This doesn't mean they don't have issues, they do, it just isn't as visible and is better managed. It is MICs and LICs that have the fastest growth and the largest populations, creating visible inequalities and urban planning chaos.
Case Study - Mumbai
Mumbai's hyper-urbanisation
- Mumbai has always been a significant trading point and remains the wealthiest city on the north-west coast of India 
- Originally a number of separate islands, Mumbai was joined through large-scale land reclamation and causeway projects 
- Mumbai is India's most populous city and its growth has been large but steady 
- In 1950, Mumbai had a population of 1.6 million people and increased 10-fold to 16 million by 2000 
- Most of the growth is through in-migration from rural areas and due to limited physical expansion, Mumbai has the second highest population density in the world with 26,357 persons per km2 
- Mumbai has more million and billionaires than any other Indian city, but also the highest rates of poverty 
Map of Mumbai

Mumbai's importance to India
- Commercial and financial capital of India - Growth is in hi-tech, call centres and online banking 
- 60% of India’s trade is through Nhave Sheva container port 
 
- Approximately 3 million people commute daily into the city 
- Mumbai contributes 40% of India's entire tax revenue 
Global importance
- Most globalised city in SE Asia 
- Has the largest number of TNCs (inc. GlaxoSmithKline, Volkswagen, Tata Steel) 
- 40% of international flights to India arrive in Mumbai 
- Global transport hub (connecting point for transport links) connects all industrialised cities in India 
- Largest foreign investment centre 
- Home to the largest film industry in the world - Bollywood 
- Centre for design and fashion 
Overview of the Consequences of Mumbai's Megacity Growth
| Individual Consequences | Societal Consequences | 
|---|---|
| 75% of Mumbai's population live in slums - Dharavi is 2 km2 and is the largest in India with over 1 million people 80% of dry waste is recycled by inhabitants of Dharavi Literacy rate in Mumbai is 89.73  The sex ratio in Mumbai city is 853 females per 1000 males Per capita income is 3xs the national income | Pressure on services and education High population density -crowded and confined conditions 11,000 tonnes of rubbish is produced daily, making Mumbai the most wasteful city in India Lack of water resources - sewage, untreated industrial waste and oil are dumped into waterways, contaminating fresh water Energy infrastructure is not sufficient to accommodate growing needs Disparity between rich and poor - Dharavi's slums at risk of development to make way for more business | 
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