In a world where population has spiraled out of control the cities have become so densley populated that each square mile has over 400,000 inhabitants.

Each town ranges in size between 12 to 15 square miles in size.

People live in skyscraper size high-rise flats which are separated by roads used for delivery, walking and government authorised vehicle travel only.

All transport is done via an underground subway system or by air travel for the super rich.

All necessaries, such as food and sanitary products, are available from vending machines spread throughout the streets and buildings.

At the centre of each town there is a complex containing government departments, luxury shops, hospitals, pharmacies, clinics and areas to congregate during hours designated for your social group by the government.

Bearing in mind these complexes are very cramped, how big would they need to be to support such a high density of people and what health issues would be an issue within the complex?

  • $\begingroup$ How big is each city? I mean, if the entire city is in a single square mile, you've only got 250K people, but if the city has a 20 mile radius, you're dealing with closer to 314 million people. That's gonna make a little bit of a difference. $\endgroup$
    – Rob Watts
    Feb 15, 2017 at 20:33
  • $\begingroup$ Sorry, I edited that it by mistake. I'll put it back in. $\endgroup$
    – Terry
    Feb 15, 2017 at 20:34
  • $\begingroup$ For reference, that population density is comparable to parts of Hong Kong. Mong Kok has 340,000 people per square mile. $\endgroup$
    – Rob Watts
    Feb 15, 2017 at 20:39
  • 3
    $\begingroup$ Where is the food (and other products, for that matter) being produced? That would break my suspension of disbelief -- badly. $\endgroup$
    – user
    Feb 15, 2017 at 20:47
  • 4
    $\begingroup$ Prisons probably have regulations for minimum space for various functions, possibly with studies to back up the why's. $\endgroup$
    – user25818
    Feb 15, 2017 at 21:06

3 Answers 3


A lot of this depends on wealth.

While population density is high, about 4 times the current global maximum, there's no reason for it to be that much of a problem. If the apartments are well built and give families enough basics, if there's work, food and healthcare, it could just be a well regulated city. Dhaka has a population density of around 115,000/sqm. It's not massively high rise, just consistently 6-7 story buildings still set in space.

By preventing people from driving you've significantly reduced the air pollution, by putting everything within an easy walking distance you've probably increased everybody's level of daily exercise.

What this comes down to is whether the towers were built for this density or whether you've got 3 extended families living in a space designed for 2 people and a baby.

For the size and situation you've given there's no reason not to build a single solid development with ground level but overbuilt service roads. The lower levels for service and commercial activities and the higher levels for residential. Parks, gardens and the "street level" for walking on are actually a couple of stories above ground level, over the roofs of the commercial levels, there's no reason for the average person to even see a motorised vehicle in their daily lives.

Hospitals and healthcare

You're apparently suggesting a single hospital per city, 1 for 5-6million population. The equivalent value in the UK is 3.5/100,000 population (not all have all services). That's equivalent to 14/sqm on your map, a little overkill but certainly a 1/sqm is not unreasonable. That's not including GP surgeries, where you'll need a GP for every 4000 people or so. Centralising your healthcare is impossible and gives you no redundancy, you'll need to spread high quality facilities widely across your city. You can have a central hospital for all the real specialist services, but anything that people need day to day, GP surgeries, pharmacies, kidney dialysis, physiotherapy, geriatric care etc. etc. should be distributed.

Coughs and colds, seasonal flu etc. could possibly run rampant, but this sort of thing still depends on the general health of the population. If the water supply is good, the plumbing is good, and the people are looked after, that should be the worst of your problems. The less you centralise the slower diseases will spread. If everyone goes to the same place for their healthcare then a single infectious disease could hit the whole population in short order.


As per hospitals, distributed so children have the shortest possible journey to school for the duration of their compulsory education.

Government services

These can be centralised, they're more about area coverage than population. You'll need some system of constituency representation to be able to handle the population but that's administrative, but there's no reason they shouldn't be able work out of a single building. As per waste collection etc.

Social centres

Again these need to be decentralised, as much for control of population as anything, you don't want too many people in one place if things get a bit rocky. You want nice controllable population elements so if one sector goes bad it doesn't spread so rapidly across the whole city.


Population density has made plumbing critical infrastructure and hence a government service. It can't be risked to the private sector.

It doesn't have to be a dystopia

but let's make it a dystopia anyway.

So far we've decentralised to a limited extent. Now we need to isolate people. One of the great failings with modern megacities is their excessive centralisation. People commute for hours to get to a job that barely pays the rent and transport costs. Welcome to the new utopia, no more commuting, everything you need is in your home tower. Your job, shops, gym and healthcare are all no more than a few stories from your home.

Excuse me sir, can you fill in a short survey on why you need to leave your home tower today? Is some facility lacking?

Well that's how it starts. Luxury gated estates are all the rage these days, people feel safe if other people can't get in. Gates work both ways though.

Halt, do you have a transit permit?

It won't take long to change from one to the other. Excessive movement of people puts excess load on the system, it means the logistics become complicated, the government won't know where to send resources causing waste in a system that must be efficient. The system must know where everyone is, people should stay where they're put.


You have stated that your cities are 12 to 15 sq miles in size. This means each city would have 4.8 to 6 million people. While the population is normal for big cities. The only difference in your scenario is that the city's physical boundaries are very tight.

The area in the center of your cities has 3 types of buildings. Health facilities, government buildings, shops. So we need to decide the least area required for serving 6 million people in these categories. If most of government facilities are available on the internet (as in, you could file police complaints etc over the internet without the need to go to the police station), then that area could be made smaller by squeezing the streets and making lounge places smaller. Next are health services. Again, if people could file health complaints through internet and government sends hospital vans with most of everyday devices and medical staff, people could get diagnosed at their doorsteps without needing to physically visit the hospitals. Finally, people could order things from shops over the internet and the city wide courier service would deliver their goods at their doors. This way, you could decrease the rush at the shop area too (thus requiring smaller space for the shop area).

If all services are available at doorstep through internet, then I would think that you would need to reserve about 1.5 mile at the center of each city for all the different buildings. However, if people need to physically visit all the places (for official matters, health services and shopping) then you would need to reserve 3 miles at the core of each city for these types of buildings.

  • $\begingroup$ 10-25% for a town center seems like a reasonable range, but can you maybe flesh out your reasoning? $\endgroup$
    – user25818
    Feb 16, 2017 at 0:16
  • $\begingroup$ Why centralise? Spread smaller facilities around the city. $\endgroup$
    – Separatrix
    Feb 16, 2017 at 8:33
  • $\begingroup$ @Separatrix OP asks for a centralised complex at the centre of each city $\endgroup$
    – Secespitus
    Feb 16, 2017 at 8:50
  • $\begingroup$ @Secespitus, you're right, he does $\endgroup$
    – Separatrix
    Feb 16, 2017 at 8:58
  • 1
    $\begingroup$ @Mołot for trousers I'd rather not go to Oxford Street when I could go to my local high street. There may be less choice but it's a lot less stressful. A single retail district for 5million people will be as close to hell as shopping can get. $\endgroup$
    – Separatrix
    Feb 16, 2017 at 9:58

Six million people in a crowded, highly regulated society. A dystopia?

Decide how many people you get in each social class. Say that half the people are of working age, the others are children/students or pensioners. Also assume that pensioners retain the class they had in working age and that children are classed with their parents, so that evens out. (Keep in mind that numbers could be reduced a little by tweaking this.)

One could start calculating the number of police, of teachers, etc. 1 in 200 citizens is a cop, 1 in 100 is a teacher if you count university education, etc.

Easier to say that out of every 5 workers, 1 is a foreman/team lead. Out of every 5 team leads, one is a "real manager" or "valuable expert". That's 1 in 25, or 4%. That's roughly like the number of officers in an armed force. Of course this will differ from sector to sector. The vending machine refilling department might get away with 1% leadership cadre, the domestic intelligence service has a rather higher percentage. This page quotes estimates that 30% of the North Korean population are privileged classes. That would be a rough match to my guesstimate of team leads.

So you get 240,000 people who have access to luxury shops, etc. How long are they using those facilities each day? How large are they? Say half an hour shopping per day, and these important people will not shop at 0-dark-30. 15,000 shopping at any one time. A million square metres, ten million square feet, of shops?


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