aimnova.
DashboardMy LearningPaper MasteryStudy Plan

Aimnova site navigation

Stay in the loop

Get the latest study resources and updates

New features, study tips and exam insights — straight to your inbox.

IB Diploma

  • IB Past Papers
  • IB Study Notes
  • IB Question Bank
  • IB Mock Exams
  • IB Revision

IB Subjects

  • IB Math AA
  • IB Math AI
  • IB Economics
  • IB Business Management
  • IB Physics
  • IB Biology
  • View all IB subjects→

IB Past Papers

  • IB Math AA HL Past Papers
  • IB Math AA SL Past Papers
  • IB Math AI HL Past Papers
  • IB Math AI SL Past Papers
  • IB Economics HL Past Papers
  • IB Economics SL Past Papers
  • IB ESS Past Papers
  • View all past papers→

Study Resources

  • Study Notes
  • Question Bank
  • Mock Exams
  • Flashcards
  • Revision Guide
  • Exam Skills
  • Command Terms
  • Grade Calculator
  • Exam Timetable 2026

Aimnova

  • Features
  • Pricing
  • For Teachers
  • For Schools
  • For Parents
  • About Us
  • Blog
  • Contact
aimnova.

AI-powered study platform for smarter revision, past-paper analysis and examiner-style feedback.

TermsPrivacyCookies·© 2026 Aimnova. All rights reserved.d011a78

Aimnova is not affiliated with or endorsed by the International Baccalaureate Organization (IB).

NotesGeographyTopic 13.2Urbanisation, megacities and urban growth
Back to Geography Topics
13.2.18 min read

Urbanisation, megacities and urban growth

IB Geography • Unit 13

Smart study tools

Turn reading into results

Move beyond passive notes. Answer real exam questions, get AI feedback, and build the skills that earn top marks.

Get Started Free

Contents

  • Urbanisation, megacities and urban growth
  • Reading urban-growth data
  • Why cities grow — and why some slow down
  • Managing rapid growth and the [10] essay
The big idea: Urbanisation is the rising share of people living in towns and cities — the % of a country's population that is urban.

Don't confuse it with urban growth, which is the rise in the number of people living in a city. A city can keep growing in size even after a country is fully urbanised.

A megacity is a city with more than 10 million people (e.g. Tokyo, Lagos, Mumbai). The number of megacities has risen fastest in Africa and Asia.

Key terms for this micro

  • Urbanisation — the increasing proportion of a population living in urban areas.
  • Urban growth — the increase in the number of people living in a city.
  • Megacity — a city with a population over 10 million.
  • Natural increase — births minus deaths; a youthful city population grows itself.
  • Rural-urban migration — people moving from the countryside to the city.
  • Push factors — things driving people OUT of rural areas (poverty, drought, few jobs).
  • Pull factors — things drawing people INTO cities (jobs, schools, hospitals).
Two engines of urban growth: A city grows from two sources at once:

Natural increase — a youthful migrant population has high birth rates, so the city grows from within.

Rural-urban migration — people pulled in by city opportunities. Together these make cities in Africa and Asia grow fastest today.

Free preview

This is the free notes preview

You're reading the free notes. Aimnova Pro unlocks the full study experience — and you can try it with your first topic free to keep:

  • FlashcardsLock in vocabulary and key terms with spaced repetition.
  • Practice questionsAnswer exam-style questions and get instant AI marking.
  • Mock exams & past-paper vaultSit full mocks and see exactly how examiners award marks.
  • Personalised study planA daily plan built around your exam date and weak areas.
Start Studying Free Full access to Aimnova Pro · cancel anytime
How this is tested: A line graph of urban share rising over time (or an infographic of the fastest-growing cities) is the usual stimulus for the data part of an urban-environments question. The reading skills are State or Identify a value off the axis — a region's urban %, the year the world passed 50% urban — and Estimate a figure that sits between the gridlines. Pick the right line and axis and always quote the units (% urban).

Read the key first. Follow ONE line, read its value off the left axis, and quote the units (% urban).

Interactive diagram

Explore the labelled diagram, charts and maps for this topic in full study mode.

Claim your free topic
IB-style questionEstimate[2 marks]

Using the graph above, estimate the year in which Asia's population first became more than 50% urban.

Model answer plan

See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.

Claim your free topic
Region19802020Projected 2050
North America748389
Latin America & Caribbean658188
Europe677584
Asia275166
Africa274459
World395668
State vs Estimate vs Identify: State = give the exact value shown (e.g. read 51 straight off the table).

Estimate = a sensible value read between marks or off a map scale.

Identify = name the place, feature or category the data points to.
IB-style questionState[3 marks]

Using the table above: (a) state the % of Asia's population that was urban in 2020; (b) identify the region that was most urbanised in 1980; (c) state the projected world urban share in 2050.

Model answer plan

See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.

Claim your free topic

Get feedback like a real examiner

Submit your answers and get instant feedback — what you did well, what's missing, and exactly what to write to score full marks.

Try AI Tutor FreeYour first topic is free to keep • No credit card required

Cities grow because more people are added than leave — through natural increase (births over deaths) and rural-urban migration.

Examiners split the causes into demographic, economic and social, and a question often asks for one type only — read the command carefully, because a 'social' answer earns nothing on an 'economic' question.

TypeCauseHow it grows the city
DemographicNatural increaseA youthful migrant population has high birth rates, so the city grows from within
EconomicBetter-paid jobsFactories and services pay more than rural farming, pulling in migrants
SocialSchools & hospitalsFamilies move for education and healthcare unavailable in the countryside
SocialRural push factorsDrought, conflict or land shortage drive people off the land

Social vs economic vs demographic

  • Demographic — natural increase (a youthful, high-birth-rate population).
  • Economic — jobs and higher wages in factories and services.
  • Social — schools, hospitals, family ties, escaping rural hardship.
  • On a question asking for ONE type, a cause of another type scores zero.
IB-style questionSuggest[4 marks]

A megacity such as Lagos is growing very rapidly. Suggest two social reasons that help explain why its population grows so quickly.

Model answer plan

See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.

Claim your free topic
Always give the mechanism: Don't just name a cause — explain how it grows the city. Better hospitals -> families migrate for healthcare -> more people in the city. And match the type the command asks for.
Why some cities slow — Tokyo and Europe: Not every city keeps booming. Tokyo, the world's largest city, is now barely growing or shrinking — Japan's birth rate is very low and rural-urban migration has run its course.

Across much of Europe and North America, urbanisation is already near its ceiling (75-85%), so the urban share rises only slowly. Growth slows when birth rates fall, the rural population to draw on runs out, or people start moving back out (counter-urbanisation).
IB-style questionOutline[2 marks]

In some continents urban populations are now growing more slowly. Outline one reason for this slower growth and develop how it works.

Model answer plan

See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.

Claim your free topic
The challenge of rapid growth: When a city grows faster than its infrastructure can keep up, services are overwhelmed. New arrivals build informal settlements (slums) on cheap, often risky land, with no piped water, sewerage or secure jobs.

The core management challenges are housing, clean water and sanitation, jobs, transport/congestion, and waste and pollution — all of them strained by the scale and pace of growth.
CityGrowth storyUse it for
Lagos, NigeriaAfrica's largest city, ~15-20m and rising fast; huge informal settlements (Makoko)Rapid growth + housing/water stress
Kinshasa, DR CongoOne of the fastest-growing cities on Earth, driven by high natural increasePace of growth + jobs/services gap
Mumbai, IndiaDharavi is one of Asia's largest informal settlements; severe congestionSlums + transport/sanitation
Tokyo, JapanWorld's largest city but now barely growing - low birth rateWhere growth has SLOWED
How this is tested - the [10] Examine essay: Paper 1 Option G ends with a 10-mark markband essay. Two recurring versions:

Examine the management challenges of rapidly growing cities, and To what extent has urban growth been matched by better infrastructure.

Top band needs: accurate terms, two or more developed challenges with a named city, a weighing of how growth's scale and pace drive them (or how far infrastructure has kept up), and a justified conclusion.
IB-style questionExamine[10 marks]

Examine the management challenges faced by cities that are growing rapidly through migration and natural increase.

Model answer plan

See the mark-by-mark plan — for / against / judgement, with marking guidance — in study mode.

Claim your free topic

Try an IB Exam Question — Free AI Feedback

Test yourself on Urbanisation, megacities and urban growth. Write your answer and get instant AI feedback — just like a real IB examiner.

In some continents urban populations are growing more slowly. one reason for this slower growth and develop how it works. [2 marks]

Related Geography Topics

Continue learning with these related topics from the same unit:

13.1.1Urban land use, economic activity and land values
13.2.2Deindustrialisation, gentrification and urban change
13.3.1Urban environmental stresses
13.3.2Urban social stresses and deprivation
View all Geography topics

Improve your exam technique

Command terms, paper structure, and mark-scheme tips for Geography

Previous
13.1.1Urban land use, economic activity and land values
Next
Deindustrialisation, gentrification and urban change13.2.2

15 exam-style questions ready for you

Students who practice on Aimnova improve their scores by 15% on average. Get instant feedback that shows exactly how to improve your answers.

Practice Now — FreeView All Geography Topics