Global Urbanisation & Megacities
A World That Lives in Cities
For most of human history, more people lived in the countryside than in cities. That changed in 2007. Today around 57% of the world’s population is urban, and the United Nations expects this to reach about 68% by 2050. Most of that growth will happen in low-income developing countries (LIDCs) and emerging and developing countries (EDCs). Three terms matter here. A city is a large urban settlement. A megacity has more than 10 million people. A world city exerts global influence well beyond its size, in finance, politics or culture.
The world has roughly 33 megacities (over 10 million people). Most are now in Asia — including Tokyo, Delhi, Shanghai, Dhaka and Mumbai — with growing African ones like Lagos and Kinshasa.
Where Are the Megacities and How Are They Changing?
In 1950 only New York and Tokyo were megacities. By 1990 there were ten, and by the early 2020s the count had passed 30. The shift has been clear — from advanced countries (ACs) towards LIDCs and EDCs. The fastest-growing cities now are in sub-Saharan Africa and South Asia, where populations are young and rural-to-urban migration is high. Some megacities, like Tokyo, have stopped growing or are even shrinking, because birth rates have fallen.
Why Do Cities Grow So Fast in LIDCs and EDCs?
Two forces drive rapid urbanisation. The first is migration from the countryside. People are pushed out by drought, falling farm incomes, lack of jobs or violence, and pulled towards cities by hopes of work, schools, hospitals and a more modern way of life. These reasons are called push and pull factors. The second is natural growth — many migrants are young, so birth rates inside the city stay high.
Social: shortages of housing, schools and clinics, and the rapid spread of informal settlements. Economic: rising informal sector employment, and pressure on infrastructure that limits growth. Environmental: increased traffic, air pollution, water shortages and waste-disposal problems. Some effects are positive too — cities concentrate skilled workers, ideas and businesses, helping innovation and productivity grow.
Case Study: Lagos, Nigeria
Lagos is one of the fastest-growing megacities in the world. It sits on the Atlantic coast of West Africa in southern Nigeria, on a series of islands and lagoons connected by bridges. The official population is over 15 million, and including outer suburbs the wider metropolitan area is estimated at more than 20 million. Lagos handles around 80% of Nigeria’s sea-borne imports and is the financial heart of West Africa.
Lagos in Its Region and the World
Lagos is connected to global trade through Apapa Port and the new Lekki deep-sea port, opened in 2023. Air links run from Murtala Muhammed International Airport. The city is West Africa’s film capital (Nollywood), a major fintech base for companies like Flutterwave and Paystack, and home to many regional headquarters of African and global firms. It is increasingly described as a world city for sub-Saharan Africa.
Migration and Character
Migrants come from across Nigeria, especially the rural north, and from neighbouring countries such as Benin, Togo and Ghana. Yoruba, Igbo, Hausa and many other ethnic groups live and work side by side, making Lagos a multilingual, multicultural city. Markets like Balogun and Computer Village trade in fashion, food and electronics. Music genres like Afrobeats have spread globally from Lagos studios.
Lagos has gleaming high-rise districts like Victoria Island next to vast informal settlements such as Makoko, where homes stand on stilts above the lagoon. Around 60% of Lagos residents live in informal housing.
Contemporary Challenges
Lagos faces serious urban challenges. Housing struggles to keep up with growth, so informal settlements like Makoko and Ajegunle have spread. Traffic congestion is famous — commuters spend hours in ‘go-slows’ on bridges into the islands — and air pollution from older diesel vehicles is a serious health risk. Waste collection cannot match population growth, so dumps like Olusosun have grown enormous. Flooding is worsened by climate change, blocked drains and rising sea levels.
Several strategies tackle transport. The Lagos Bus Rapid Transit scheme uses dedicated lanes to move thousands of commuters faster than cars. The Blue Line metro, running from Marina to Mile 2, opened in 2023 and aims to cut journey times from over an hour to about 20 minutes. The Eko Atlantic project is reclaiming land off Victoria Island to build a planned, flood-resilient new district powered partly by renewable energy. The Lekki port and free-trade zone are designed to spread economic activity east, away from the choked island core. None of these solves all of Lagos’s problems, but each adds capacity.