Urban Growth and the Global Urban World

🔍 What Is Urbanisation and Why Is It Happening?

Figure 1: Urbanisation is a rising share. A bigger share of the world's people live in towns and cities each time, and the share is still projected to rise.

Source: United Nations, World Urbanization Prospects 2018. The 2050 bar is a projection.

Urbanisation is the increase in the proportion of a country's population that lives in towns and cities, rather than rural areas. Notice that it is a proportion, not an absolute number — a country's urban population can grow while its rural population also grows, but if urban areas are growing faster, urbanisation is occurring.

Two things drive urbanisation. The first is rural-to-urban migration — people physically moving from the countryside to cities. The second is natural increase — the fact that within cities, birth rates often exceed death rates, so the urban population grows even without new arrivals. In many rapidly urbanising cities, both forces are acting simultaneously, which is why growth can be so dramatic.

Why Do People Leave Rural Areas? Push Factors

No one leaves their home village because they feel like a change of scenery. They leave because something is pushing them out — making rural life difficult, insecure or unrewarding. The most powerful push factors are:

Why Do Cities Attract? Pull Factors

Push factors explain why people leave. Pull factors explain why cities specifically become the destination. The key word here is perceived — cities often appear more attractive from the outside than the reality migrants actually find. But the perception is powerful enough to drive migration regardless.

The Urbanisation Spiral

These forces combine into a self-reinforcing process. Understanding this chain is essential for exam answers:

🗺️ Where Urbanisation Is Happening — and Why the Pattern Matters

Urbanisation is not happening everywhere at the same pace. The global pattern tells a story about where in the world development is currently occurring most rapidly — and that pattern has shifted dramatically in recent decades.

High-Income Countries (HICs) — Urbanisation Already Complete

In the United Kingdom, the United States, Japan, Germany and other HICs, urbanisation largely happened during the 18th and 19th centuries, driven by the industrial revolution. In the UK, the proportion of the population living in cities went from around 20% in 1800 to over 70% by 1900. Today, 83% of the UK population is urban — this proportion is growing only very slowly. The same is true across Western Europe, North America, Japan and Australia. Urban growth in HICs is mostly a thing of the past.

Low-Income Countries and NEEs — Where Growth Is Happening Now

The fastest urbanisation in the world today is concentrated in sub-Saharan Africa and South Asia. Countries like Nigeria, Ethiopia, Democratic Republic of Congo, Bangladesh, India and Pakistan are experiencing the same transformation that Britain went through in the industrial revolution — but compressed into a far shorter timeframe, with far larger populations, and often without the equivalent infrastructure investment.

This difference in pace matters. Britain's urbanisation took over a century. Nigeria's is happening in decades. The result is that cities cannot build roads, sewers, schools and hospitals fast enough to keep up with incoming populations — which is why informal settlements grow so rapidly.

The Rise of Megacities

A megacity is defined as an urban area with a population exceeding 10 million people. In 1950, only two cities on Earth met this threshold: New York City and Tokyo. By 2020, there were over 30 megacities worldwide. And crucially, the geography of megacities has completely shifted. In 1950, the dominant megacities were in North America and Europe — the rich world. Today, the majority are in Asia, South America and Africa.

The table tells the whole story: Delhi grew by 2,000%, Lagos by over 6,000%. London barely moved.

This shift — from European/North American megacities to Asian and African megacities — is not just a demographic curiosity. It reflects the entire arc of global development. As economic growth and industrialisation spread to South Asia and sub-Saharan Africa, the same urbanisation forces that built New York and London in the 19th century are now building Delhi and Lagos in the 21st.

🌍 Lagos, Nigeria: Africa's Megacity in Full Throttle

If you want to understand what rapid urbanisation looks like in reality — the chaos, the opportunity, the inequality, the ingenuity, the sheer overwhelming scale of it — Lagos is the place to look. There is no city on Earth quite like it.

Lagos sits on the south-west coast of Nigeria, on a peninsula and network of islands jutting into the Atlantic Ocean along the Gulf of Guinea. At independence in 1960, the city had around 760,000 people. Today, official figures put the population at around 15 million, but unofficial estimates — accounting for the millions living in informal settlements who are never counted — reach 21 million or more. Lagos is almost certainly the largest city in Africa, and one of the fastest-growing cities anywhere on Earth.

The city is Nigeria's economic capital (the political capital is Abuja, 500 km to the north), its main port, and its cultural heartland. Nigeria is Africa's most populous country with over 220 million people, and Africa's largest economy by GDP. Lagos is the engine of all of that.

Why Lagos Grew So Fast — The Causes of Its Growth

Lagos's extraordinary growth is the product of several converging forces, all acting simultaneously:

💼 The Opportunities Urban Growth Creates in Lagos

It would be easy to describe Lagos purely through the lens of its challenges — the traffic, the flooding, the informal settlements. But that would be deeply misleading. Lagos is also a place of extraordinary energy, cultural production, technological innovation, and economic aspiration. For millions of its residents, the city genuinely represents a better life than what they left behind.

Economic Opportunities

Lagos generates approximately 25% of Nigeria's GDP despite containing only 7% of its population. This concentration of economic activity creates opportunities at every level of the income spectrum.

Nollywood — Nigeria's film industry, largely based in Lagos — produces over 2,500 films a year and generates approximately $1 billion annually, making it the second-largest film industry in the world by volume (after India's Bollywood, ahead of Hollywood). Nollywood employs hundreds of thousands of Nigerians directly and millions more indirectly, from costume-makers to cinema operators. It is also a source of enormous national pride — Nigerian stories, Nigerian faces, for Nigerian and global audiences.

Lagos is developing into a technology hub. The Yaba district — nicknamed "Yabacon Valley" — is home to hundreds of Nigerian tech start-ups developing fintech (financial technology), e-commerce, and mobile payment systems. Companies like Flutterwave and Paystack (acquired by Stripe for $200 million in 2020) have emerged from Lagos. In a country where over 40% of adults were previously unbanked, mobile banking and fintech start-ups have expanded financial inclusion dramatically. Lagos's young, ambitious population is driving a genuine tech revolution.

The Lagos Stock Exchange is sub-Saharan Africa's largest, and the city hosts the headquarters of most of Nigeria's major banks, insurance companies, and multinational offices. For workers in formal finance and business services, Lagos salaries are among the highest in Africa.

Social Opportunities

Even for Lagosians who are not working in Nollywood or tech, the city offers social improvements over rural alternatives. Lagos State has a higher density of hospitals, clinics, secondary schools, and universities than any rural area of Nigeria. Lagos University Teaching Hospital provides specialist medical care unavailable in most of Nigeria. The University of Lagos offers higher education to tens of thousands of students. For a family migrating from a remote village in Kano State where the nearest secondary school is 30 km away, Lagos represents genuine educational opportunity for their children.

Women in Lagos have access to formal employment, education, and economic independence at levels not available in many rural areas where traditional gender roles are more rigidly enforced. Urban life, for many Nigerian women, represents emancipation.

Infrastructure Improvements

Lagos State Government has invested significantly in infrastructure. The Bus Rapid Transit (BRT) system launched in 2008, now carries approximately 200,000 passengers per day along dedicated lanes that bypass normal traffic. It is one of the most successful BRT systems in Africa. The Lagos Light Rail project, under construction, will add further mass transit capacity.

The most spectacular infrastructure project is Eko Atlantic City — a land reclamation project off Victoria Island creating 10 square kilometres of new land from the Atlantic Ocean, designed to house a modern financial district and residential area for Lagos's growing middle class, while simultaneously acting as a coastal barrier against sea-level rise and erosion. It is one of the most ambitious urban development projects anywhere in the world.

⚠️ The Challenges of Rapid Urban Growth in Lagos

For all its energy and opportunity, Lagos also faces challenges that are the direct consequence of growth outstripping the infrastructure available to support it. These are not inevitable features of cities — they are the result of a city growing faster than any planned system can accommodate.

Housing and Informal Settlements

Between 60 and 70% of Lagos's population live in informal housing — dwellings built without planning permission, often from salvaged materials, without mains water or sewerage connections, and at densities far beyond what any housing code would permit. Ajegunle, Mushin, Agege, Bariga — these are neighbourhoods where entire families of six share a single room, where the narrow alleyways between dwellings never receive direct sunlight, and where landlords charge for every bucket of water because there is no running tap.

The most famous of Lagos's informal settlements — and one of the most remarkable communities anywhere on Earth — is Makoko. Built on stilts over Lagos Lagoon, Makoko is a floating community of approximately 100,000 people living in wooden houses on stakes driven into the lagoon floor. Residents fish, trade, cook, sleep, and raise children on the water. There is no mains water, no sewerage system, no formal electricity grid. Children paddle canoes to school. Waste goes directly into the water. Cholera and other waterborne diseases are a constant risk.

In 2012, Lagos State Government issued an eviction notice to Makoko, demolishing houses and displacing approximately 30,000 people in a single operation, describing the settlement as a health hazard and an obstacle to development. The evictions were immediately controversial — 30,000 people lost their homes in days, with no alternative housing provided. Makoko has since partially rebuilt. The episode illustrates the brutal tension at the heart of urban development in Lagos: the government wants a modern city; a third of its residents live in informal settlements.

Traffic and Transport

Lagos is, by most international measures, one of the worst cities in the world for traffic congestion. The Oshodi area near the central market creates gridlock that can trap vehicles for four to six hours. Workers in Lagos commonly spend three to five hours per day commuting — time that cannot be spent earning, caring for children, or sleeping. The economic cost of Lagos's congestion is estimated at over $1 billion per year in lost productivity.

The root cause is straightforward: a city that grew from 300,000 to 21 million people in 70 years, in a physical geography of narrow peninsulas and lagoon islands that makes road building difficult, and where most of that growth happened in informal settlements with no road planning. The result is a city whose road network cannot cope with its population at almost any hour of the day.

Sanitation and Water

Approximately 40% of Lagos residents lack access to safe, piped drinking water. Most of the city's informal settlements have no sewerage connection — waste goes into open drains, which empty into the lagoon and ocean. The Lagos Lagoon, which should be one of the city's great assets, receives enormous quantities of untreated sewage and industrial waste, making it one of the most polluted bodies of water in West Africa.

Cholera outbreaks occur periodically, particularly during heavy rains when flood water mixes with open drains and overwhelms the informal drainage systems. In 2021, a cholera outbreak in Lagos killed over 100 people and infected thousands. Waterborne disease disproportionately affects the poorest residents living in the most densely crowded informal settlements.

Flooding and Environmental Hazards

Lagos is one of the world's most flood-vulnerable cities. Its physical geography — low-lying, on a lagoon, adjacent to the Atlantic Ocean — makes it inherently exposed to both coastal flooding and river flooding. Victoria Island, the wealthiest part of the city, floods regularly during intense rainfall because its storm drainage system cannot handle extreme rainfall events. Climate change is making this worse: sea levels are rising, rainfall is becoming more intense, and the Atlantic coastline is eroding.

In informal settlements built on low-lying land, flooding is annual and devastating. Homes are inundated, possessions destroyed, diseases spread through flood water. Residents of Makoko experience this as a routine feature of their lives, not an exceptional disaster.

Lagos is also grappling with e-waste — electronic waste from discarded computers, phones and electrical equipment shipped illegally from Europe and North America. Agbogbloshie in Ghana is the most famous example in West Africa, but Lagos also receives significant volumes of e-waste, which is often processed by hand-burning in informal areas, releasing toxic heavy metals into the soil and air.

Inequality and Crime

Perhaps the sharpest challenge in Lagos is the coexistence of extreme wealth and extreme poverty within the same city. Victoria Island and Ikoyi — the wealthy islands at the south of the city — contain gated housing estates, luxury shopping malls, five-star hotels, and restaurants where a meal costs more than a week's wages for most Lagosians. Drive 15 minutes north across Third Mainland Bridge and you are in Mushin or Ajegunle, where open sewers run alongside unpaved alleys and a family of six shares a room the size of a large bathroom.

This inequality generates social tension. Lagos has high rates of petty crime, and armed robbery — known locally as "one-chance" schemes where taxi passengers are robbed — is a well-known risk. The wealthy response is to retreat behind ever-higher walls and hire private security, which further deepens the social distance between communities.