Where are the world's largest cities?

An astronaut's eye view of urbanisation. Image: Getty.

Every year or so, Demographia, the St. Louis-based consultancy, publishes the World Urban Areas Report – a sort of bumper book of city population stats.

The report is a veritable treasure trove of demographic stats for city nerds. If you want to know whether, say, Edinburgh is one of the 1,000 biggest cities in the world, then Demographia will tell you. (It's not, it's just outside at joint 1017th). And if you want to know whether Paris covers a bigger land area than London, it'll tell you that, too. (It does: 2,845km2, as opposed to 1,738 km2.)

It even includes estimates for the size and density of hundreds of towns so tiny that you're slightly surprised to find that anyone on the other side of the Atlantic has even noticed they exist. (Favourite example: Kidderminster*.)

But the most fun is to be found in the first half of the report. Table 1 includes the 1,022 built-up areas in the world that house 500,000 people or more, ranked in order of population; Table 2 ranks the same cities in order of land area.

I don’t know about you guys, but we are stoked.

via GIPHY

(*55,000 people in 16 km2, giving a population density of 3,400 per km2, since you ask.)

Understanding the numbers

Explanations first. The report defines urban areas as

...a continuously built up land mass of urban development that is within a labour market (metropolitan area or metropolitan region)... [and] contains no rural land.

We should probably also note the reports caveat, about the limits of its own methodology:

Revisions are made as more accurate satellite photographs and population estimates become available. As a result, Demographia World Urban Areas is not intended for trend analysis.

Year-to-year changes indicated in population and land area may merely reflect better data that was not used before and may not, therefore indicate a trend.

In other words, if this year's report has a larger estimate for a city's population than last year's report, that might mean the city has grown. Then again, it might just mean that new, more accurate data has appeared.

Moreover, nearly all of the data is estimated. Appropriate caution is therefore advised.

Spoilsports.

The biggest cities, by counting people

Anyway, let’s get to the fun bit. Here are the 10 largest cities in the world by population:

It’s pretty familiar stuff. The top 10 is dominated by Asian cities, with a strong showing from New York City. Tokyo is far in the lead, with Jakarta and Delhi coming up behind. For anyone who pays any attention to this stuff, there aren't at first glance any massive surprises.

We're not supposed to compare with last year's figures for all the reasons laid out above, but what the hell, here's the 2015 top 10:

There are two big differences worth noting. One is that only one Chinese city is now in the top 10, down from three last year. (Beijing and Guangzhou are now ranked 11th and 13th.) All three have seen their populations revised downwards: this seems to the result of previous over-estimates, rather than mass evacuations.

The other noteworthy trend is the sudden appearance in the top 10 of Mumbai, with nearly 23m people. Last year, it ranked 13th with 17.7m. In a section headed "Revised data: highlights", the report notes:

The Mumbai built-up urban area has been expanded to incorporate the Bhiwandi, Kalyan and Vasai-Virar urban areas.

In other words, it isn't that a population the size of Madrid has moved to Mumbai over the last year. Rather, it's become clearer that the megacity has expanded to swallow surrounding areas.

You can see why ranking cities is a complicated business.

The biggest cities, by measuring land

As noted, most of the biggest cities in the world by population are in Asia. Most of the biggest cities in the world by physical size are, well, somewhere else.

Suddenly, with the single exception of Tokyo, Asia doesn’t even feature. Eight out of 10 are in the US. Atlanta has an estimated 5.1m residents, so measured by population it’s the 79th largest city in the world. Measured by land area, though, it ranks fourth.


I guess this is what happens when you build your cities around the car.

Incidentally, the report estimates Atlanta's population density to be 700 people per km2. The comparable figure for Dhaka in Bangladesh – 16.2m people, the 16th largest city in the world - is 44,100.

Dhaka is 63 times more crowded than Atlanta.

All the megacities

One more chart: this is the top 36 by population.

The reason we've stopped at that arbitrary point is not to get London into the rankings (well, not only for that reason). It's because the common definition of megacity is that with a population over 10m.

This is all of them. We've colour coded them by continent:

That's three each in North America, South America, Europe and Africa.

But the remaining 24 – two thirds of all the world's megacities – are in Asia. Five of them are in China alone.

Here, because we love you, is the data used in that graph. Enjoy.



Rank City Population
1 Tokyo-Yokohama 37,750,000
2 Jakarta 31,320,000
3 Delhi 25,735,000
4 Seoul-Incheon 23,575,000
5 Manila 22,930,000
6 Mumbai 22,885,000
7 Karachi 22,825,000
8 Shanghai 22,685,000
9 New York City 20,685,000
10 Sao Paulo 20,605,000
11 Beijing 20,390,000
12 MexicoCity 20,230,000
13 Guangzhou-Foshan 18,760,000
14 Osaka-Kobe-Kyoto 16,985,000
15 Moscow 16,570,000
16 Dhaka 16,235,000
17 Cairo 15,910,000
18 Bangkok 15,315,000
19 Los Angeles 15,135,000
20 Kolkata 14,810,000
21 Buenos Aires 14,280,000
22 Tehran 13,670,000
23 Istanbul 13,520,000
24 Lagos 12,830,000
25 Shenzhen 12,240,000
26 Rio de Janeiro 11,815,000
27 Kinshasa 11,380,000
28 Tianjin 11,260,000
29 Lima 10,950,000
30 Paris 10,870,000
31 Chengdu 10,680,000
32 Lahore 10,355,000
33 London 10,350,000
34 Bangalore 10,165,000
35 Ho Chi Minh City 10,075,000
36 Nagoya 10,035,000

 

And if you want more of this stuff, here’s our report on the 2015 edition of the Demographia World Urban Areas Atlas.

Jonn Elledge is the editor of CityMetric. He is on Twitter, far too much, as @jonnelledge.

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How autonomous vehicles might actually make cities more dependent on cars

An autonomous car in action. Image: Getty.

Cities across Europe are taking steps to become increasingly car free. London mayor Sadiq Khan is aiming for 80 per cent of all trips to be made on foot, by cycle or using public transport by 2041, while Copenhagen authorities are aiming for three quarters of all trips to be made in these ways by 2025. Policymakers in Paris want to halve the number of private cars in the city centre, and Madrid will ban all non-resident vehicles except zero-emission delivery vehicles, taxis and public transport from its city centre in November 2018. In Helsinki, the aim is to phase out the use of private cars by 2050, by providing on-demand, affordable public transport.

Alongside reducing congestion and improving urban mobility, city leaders are expected to promote sustainable economic growth, improve air quality and respond to concerns from residents – all within tight budgets. In a world where talent and investment are increasingly mobile, city leaders know they must compete in terms of economic dynamism and quality of life – and transport planning is one way to do that.

Boon or burden?

But car makers and tech giants are looking to a very different type of future, where private car ownership, human control and petrol and diesel engines are replaced by shared, electric and autonomous – or self-driving – vehicles. Many of these changes could be positive for society, compared to current transport systems. It is likely that autonomous vehicles will eventually be better drivers than humans, which would reduce the number of road accidents and fatalities. They may also provide much needed accessibility to elderly and disabled people, which would be beneficial not only to them, but the economy at large.

Without the need to drive, people will be able to be more productive while travelling. If people are able to call up a car at the touch of a smart phone, car ownership will drop, which will free up the substantial tracts of urban land that are currently used to park vehicles. And, with the right incentives, travellers could be encouraged to use the most efficient vehicle for each journey taken, with substantial reductions in emissions and pollution. There would also be benefits for freight deliveries, which may be able to be undertaken at night, when there is more available road capacity.

Paris: quieter by night. Image: Luc Mercelis/Flickr/creative commons.

But some changes may be negative. Self-driving cars are likely to increase – rather than decrease – car travel, as people succumb to the allure of convenience and switch from public transport, or make more journeys. Autonomous vehicles may be able to park themselves away from urban centres, but they still need to be parked – and make return journeys to collect passengers, adding empty cars to the roads and contributing to congestion and air pollution.

And there are lots of unanswered questions about how urban systems will work with the introduction of self-driving vehicles. For example, it’s not clear how self-driving vehicles will co-exist with pedestrians and cyclists. If they are programmed to stop whenever a pedestrian or cyclist gets in their way, there will be pressure to further separate vehicles, pedestrians and cyclists. The vision of future cities in the 2050s may then start to look more and more like the vision of the 1950s, with futuristic new models dominating the foreground, while human activities such as walking and cycling are relegated to concrete overpasses and gloomy subways.


Back to the future

History shows that decisions made by policy makers have long-lasting effects. For example, when automobiles first arrived in cities, policymakers in different countries took different approaches to the issue of mixing of vehicles and pedestrians. In the United States, policymakers invented the concept of “jaywalking” and introduced stringent laws to separate vehicles and pedestrians, in order to “protect pedestrian safety”. The UK, on the other hand, took a more relaxed approach, introducing no such laws.

At the other extreme, policymakers in The Netherlands have taken the view that shared spaces - where streets are designed specifically to allow interaction between vehicles, pedestrians and cyclists - improve safety for all, as well as the liveability of cities more generally. These decisions have had long-lasting impacts on how cities in these countries look and feel today.

The ConversationThe way we think think about the future for autonomous vehicles seems divorced from the wider issues of city transport strategy and economic and social sustainability. It is time to put this right. Mayors, supported by their officials and planners, should start leading a debate now about how self-driving vehicles can best serve the needs of residents and visitors, and help deliver wider goals for their cities. They must develop the policies needed to deliver these benefits, well before self-driving vehicles arrive on the streets.

Mark Kleinman, Professor of Public Policy, King's College London and Charlene Rohr, Senior Research Fellow, King's College London.

This article was originally published on The Conversation. Read the original article.