The cities projected to double their population by 2030

Two mid-sized African capitals were on course to double in size within a single generation, according to a 2016 United Nations study — a scale of growth that puts London's crowded rush-hour into perspective. Three more cities were projected to come close behind.

The figures come from the UN Department of Economic and Social Affairs (DESA) Population Division, which in 2016 published a data booklet titled The World's Cities in 2016. It tracked the historic (2000), current (2016) and projected (2030) populations of 476 cities worldwide, drawing on estimates from World Urbanization Prospects: The 2014 Revision. The projections below are exactly that — projections made in 2016 for a horizon fourteen years out — and are presented here with that context intact, not as settled fact.

The cities on course to double

Of the 476 cities in the DESA dataset, two were projected to more than double in size between 2016 and 2030: Niamey, the capital of Niger, and Ouagadougou, the capital of Burkina Faso. Niamey was projected to grow from about 1.13 million people in 2016 to roughly 2.36 million by 2030 — its 2030 population reaching around 210% of its 2016 level. Ouagadougou was projected to grow from about 2.92 million to roughly 5.85 million over the same period, reaching about 200% of its 2016 size.

Three more cities were projected to come within a few percentage points of doubling: Dar es Salaam (Tanzania), from about 5.41 million to 10.76 million (around 199% of its 2016 population); Bamako (Mali), from about 2.65 million to 5.23 million (about 197%); and Kampala (Uganda), from about 2.01 million to 3.94 million (about 196%). All five sit in the top tier of the DESA growth table, and according to the report the twenty fastest-growing cities in the 2016–2030 projection were, without exception, in Africa.

Two African capitals, Niamey and Ouagadougou, were projected to more than double in size in the fourteen years between 2016 and 2030 — a rate of growth with no equivalent among the world's largest cities.

The wider urbanisation shift

The doubling cities sit inside a broader trend. DESA estimated that 54.5% of the world's population lived in urban settlements in 2016, and projected that share would reach 60% by 2030 — with one in every three people worldwide living in a city of at least half a million residents. Set against that backdrop, the world's very largest urban areas in 2016 were led by Tokyo (about 38.1 million), Delhi (about 26.5 million), Shanghai (about 24.5 million), Mumbai (about 21.4 million) and São Paulo (about 21.3 million), as reported in the same 2016 data booklet. None of those five were among the fastest-growing; scale and growth rate are different things, and the cities adding people fastest by percentage are, almost without exception, starting from a far smaller base.

Why Africa dominates the growth table

Regionally, DESA's 2016 dataset put Africa's average city growth at the top of the table for both the historic period (2000–2016) and the 2016–2030 projection, ahead of South-Central Asia, the rest of Asia, Latin America and the Caribbean, Oceania, and Europe, which came last in both periods. That ordering tracks demographics rather than any single policy: Africa's population is younger and its fertility rates higher than Europe's or East Asia's, so its cities add residents through births as well as migration from rural areas. The gap is significant — DESA's regional figures show Africa's average city reaching roughly 158% of its 2016 population by 2030, against Europe's average of around 106%, a difference of more than fifty percentage points.

Reading these forecasts with care

Two caveats are worth keeping in mind. The first concerns definitions rather than growth: the DESA dataset compares cities using boundaries that are not consistent from place to place — some figures cover a legal "city proper," others an entire "urban agglomeration" or metropolitan area. A city whose administrative boundary is redrawn or annexes surrounding districts can show enormous jumps in the data that have little to do with the number of people actually moving in. That is a genuine risk with any global city-comparison dataset, not a flaw unique to this one, and it is one reason organic population growth — the kind driving Niamey's and Ouagadougou's numbers — is a more meaningful signal than a raw percentage change.

The second caveat is that a projection made in 2016 is a forecast, not a fact, and the UN itself revisits these numbers. DESA has published newer revisions of World Urbanization Prospects since 2016 (in 2018 and again in 2022), each incorporating fresh census data, updated fertility assumptions and revised methodology. Later editions have already adjusted the trajectories for fast-growing African cities, in some cases lower than the 2016-vintage numbers implied. That does not undo the core finding — Niamey and Ouagadougou remain consistently near the top of every UN growth ranking — but it is a reminder that a "2030 population" quoted from any single year's report is a working estimate, due to be revised again before the horizon year arrives.

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