Urban Issues and ChallengesTopic Summary
Topic Summary: Megacities and Rapid Urban Growth
Part of Urban Sustainability and Megacities — GCSE Geography
This topic summary covers Topic Summary: Megacities and Rapid Urban Growth within Urban Sustainability and Megacities for GCSE Geography. Revise Urban Sustainability and Megacities in Urban Issues and Challenges for GCSE Geography with 15 exam-style questions and 20 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 14 of 14 in this topic. Use this topic summary to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 14 of 14
Practice
15 questions
Recall
20 flashcards
Topic Summary: Megacities and Rapid Urban Growth
Key Terms
- Megacity: City with 10m+ population
- Rural-urban migration: People moving from countryside to city
- Push factor: Drives people FROM rural areas
- Pull factor: Attracts people TO cities
- Informal settlement: Housing built without legal permission
- Top-down development: Led by governments / large organisations
- Bottom-up development: Community-led approaches
- NEE: Newly Emerging Economy (e.g. India, Brazil)
Key Data
- 1950: 2 megacities → 2024: 37 megacities
- 90% of megacity growth in LICs/NEEs (Africa/Asia)
- Dhaka: 22.5m people, +300,000/year
- Mumbai: 21.4m people, 6.6% of India's GDP
- Dharavi: 1m people, 2.4km², £1bn economy
- 1 billion people globally in informal settlements
- Mumbai traffic: 10 km/h; Dhaka traffic: 7 km/h
- Urban wages: 3–5× higher than rural wages
Case Studies
- Mumbai (NEE): Dharavi slum with £1bn economy; flooding 2005 (944mm/day); Mumbai Metro Line 3 (33.5km); Slum Rehabilitation Authority
- Dhaka (LIC): 40% in bastis; Rana Plaza 2013 (1,134 dead); BRAC reaches 100m people; ADB flood embankments
- Rio de Janeiro: Favela-Bairro — community upgrades not demolition
- Seoul: Demolished urban highway → restored Cheonggyecheon stream
- Singapore: Certificate of Entitlement system limits car ownership
Must-Know Facts for Exams
- Name your city in sentence 1 of any case study answer
- Use TRAFFIC acronym for megacity challenges
- Top-down: better for infrastructure at scale
- Bottom-up: better for reaching marginalised communities
- Best approaches combine both (e.g. Favela-Bairro)
- Informal settlements are NOT just poverty — Dharavi has a £1bn economy
- Dhaka = LIC | Mumbai = NEE | Tokyo = HIC (know the difference)
- Climate change is worsening megacity flooding — link topics for synoptic marks