# World's biggest metropolis **URL:** \ **Category:** Factual Questions\ **Created:** [May 17, 2001, 4:52am UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690 "2001-05-17T04:52:05Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Mats\_K](https://avatars.discourse-cdn.com/v4/letter/m/8edcca/32.png) [@Mats\_K](https://boards.straightdope.com/u/Mats_K)\ **Post date:** [May 17, 2001, 4:52am UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690/1 "2001-05-17T04:52:05Z")
Does anybody know which city has the world’s biggest metropolis? ---
**Author:** ![bibliophage](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bibliophage/32/7615_2.png) [@bibliophage](https://boards.straightdope.com/u/bibliophage)\ **Post date:** [May 17, 2001, 5:30am UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690/2 "2001-05-17T05:30:13Z")
Depends on what you mean by “metropolis”. The population within the city limits isn’t necessarily a good measure, because some cities include suburban-type neighborhoods and some suburbs include urban-type areas. The United Nations defines what it calls “urban agglomerations” of densely populated areas irrespective of city limits. Their list of the top ten is [ul]1/ Tokyo, Japan 26.4 million 2/ Mexico City, Mexico 18.1 million 3/ Mumbai (Bombay), India 18.1 million 4/ Sao Paulo, Brazil 17.8 million 5/ New York, United States 16.6 million 6/ Lagos, Nigeria 13.4 million 7/ Los Angeles, United States 13.1 million 8/ Calcutta, India 12.9 million 9/ Shanghai, China 12.9 million 10/ Buenos Aires, Brazil 12.6 million[/ul] [http://www.earthtimes.org/feb/developmentgrowthofurbanfeb21\_01.htm](http://www.earthtimes.org/feb/developmentgrowthofurbanfeb21_01.htm) ---
**Author:** ![Mats\_K](https://avatars.discourse-cdn.com/v4/letter/m/8edcca/32.png) [@Mats\_K](https://boards.straightdope.com/u/Mats_K)\ **Post date:** [May 17, 2001, 5:38am UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690/3 "2001-05-17T05:38:51Z")
What about just the “city proper”? Also, the largest CBD? ---
**Author:** ![MrDeath](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@MrDeath](https://boards.straightdope.com/u/MrDeath)\ **Post date:** [May 17, 2001, 9:22am UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690/4 "2001-05-17T09:22:44Z")
“Buenos Aires, Brazil”? ---
**Author:** ![MrDeath](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@MrDeath](https://boards.straightdope.com/u/MrDeath)\ **Post date:** [May 17, 2001, 9:26am UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690/5 "2001-05-17T09:26:58Z")
The more I look at the provided link, the more my mind boggles. In addition to Buenos Aires, Brazil, it lists “Karachi, Bangladesh” in the top 15. And _then_ it says: > [@](#): > > By 2015, it said Lagos, the Nigerian commercial capital, would become the third larbgest urban agglomeration with a population of 23.2 billion people. Let’s see, that means the population of the planet has to increase by, what, a factor of 12 in the next 14 years (just for the 3 largest metropolises alone)? Ladies, start your uteruses! ---
**Author:** ![astorian](https://avatars.discourse-cdn.com/v4/letter/a/ad7895/32.png) [@astorian](https://boards.straightdope.com/u/astorian)\ **Post date:** [May 17, 2001, 2:34pm UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690/6 "2001-05-17T14:34:31Z")
Bear in mind that even the best estimates of population are just that: estimates, based on both hard data and good guesses. Coming up with an accurate measure of Chicago’s population is difficult enough- but getting a handle on the population in Third World cities like Rio de Janeiro, Mexico City, Cairo and Calcutta can be well nigh impossible. Every day, people move to the outskirts of these cities, and set up tents or shacks. These people don’t show up any any official forms, but they exist. Do they get counted? Who knows? I have no solid evidence to refute the Top Ten list presented earlier. It’s probably about as accurate a list as we can hope for. But, just as an example, I’ve seen some demographic studies suggesting Cairo (Egypt) may already have 20 million people! Is that true? I don’t know- but I’d hate to be the demographer sifting through Cairo, Calcutta, Sao Paolo or Lagos, trying to find the “real” population. ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [May 17, 2001, 5:05pm UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690/7 "2001-05-17T17:05:34Z")
> [@](#): > > \*Originally posted by MrDeath \* > \*\*Let’s see, that means the population of the planet has to increase by, what, a factor of 12 in the next 14 years (just for the 3 largest metropolises alone)? Ladies, start your uteruses! \*\* Birth rates are a factor, but a lot of the increase can be explained by migration into the city, as well as expansion of the urbanized area. ---
**Author:** ![Necros](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/necros/32/11086_2.png) [@Necros](https://boards.straightdope.com/u/Necros)\ **Post date:** [May 17, 2001, 7:43pm UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690/8 "2001-05-17T19:43:18Z")
**Terminus Est** , if you’re prepared to explain how even a tenth of the proposed 23 **billion** people mentioned by the report are going to move to Lagos, I’m prepared to listen. 🙂 ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [May 17, 2001, 8:46pm UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690/9 "2001-05-17T20:46:15Z")
> [@](#): > > \*Originally posted by Necros \* > \*\ ***Terminus Est** , if you’re prepared to explain how even a tenth of the proposed 23 **billion** people mentioned by the report are going to move to Lagos, I’m prepared to listen. 🙂 \*\* Uh, sure thing. People aren’t going to move Lagos, Lagos will come to them. In fourteen years, Lagos will have expanded to encompass the entire globe, a la Trantor. [sub]Yeah, that’s the ticket[/sub]:o ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [May 17, 2001, 9:40pm UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690/10 "2001-05-17T21:40:21Z")
As **bibliophage** said, the population of a metropolis depends on how you define said metropolis: [http://www.sru.edu/depts/artsci/ges/discover/d-6-9a.htm#why](http://www.sru.edu/depts/artsci/ges/discover/d-6-9a.htm#why) > [@](#): > > The central city of Tokyo, defined as 23 wards, had 8,164,000 residents and covered 598 sq. km. The Tokyo prefecture (Tokyo-to) had 11,856,000 and covered 2,162 sq. km. The Greater Tokyo Metropolitan Area (including Yokohama) had 31,559,000 and covered 13,508 sq. km. The National Capital Region in Japan had 39,158,000 residents and covered 36,834 sq. km. Finally, HABITAT estimates the 1990 population of the Tokyo “Urban Agglomeration” as 25,013,000 – giving us yet a fifth possible population to use for Tokyo in 1990! As **MrDeath** pointed out (and I completely overlooked :o), the figures that **bibliophage** cites are not completely reliable. So, the straight dope from the UN report on [Urban Agglomerations 1996](http://www.undp.org/popin/wdtrends/urb/furb.htm): ```auto Population Rank Agglomeration Country (thousands) 1 Tokyo Japan 27,242 2 Mexico City Mexico 16,908 3 Sao Paulo Brazil 16,792 4 New York United States of America 16,390 5 Bombay India 15,725 6 Shanghai China 13,659 7 Los Angeles United States of America 12,576 8 Calcutta India 12,118 9 Buenos Aires Argentina 11,931 10 Seoul Republic of Korea 11,768 ``` Growth rates vary. Lagos, Nigeria, ranked #12 with 10.9 million, will grow to 24.6 million in 2015, to be ranked #3. Tokyo, in comparison, will still be ranked #1 but will only have grown to 28.9 million. ---
**Author:** ![system](https://global.discourse-cdn.com/straightdope/original/2X/e/e489c3b7d8fce19c4b355dd4fc3f88cc39c34b87.png) [@system](https://boards.straightdope.com/u/system)\ **Post date:** [May 17, 2001, 11:06pm UTC](https://boards.straightdope.com/t/worlds-biggest-metropolis/65690/11 "2001-05-17T23:06:19Z")
> [@](#): > > \*Originally posted by astorian \* > Bear in mind that even the best estimates of population are just that: estimates, based on both hard data and good guesses. Precisely (ironic eh?) > [@](#): > > Coming up with an accurate measure of Chicago’s population is difficult enough- but getting a handle on the population in Third World cities like Rio de Janeiro, Mexico City, Cairo and Calcutta can be well nigh impossible. Every day, people move to the outskirts of these cities, and set up tents or shacks. These people don’t show up any any official forms, but they exist. Do they get counted? Who > knows? Someone tries to estimate them, but since the very same folks are often there “illegally” in some way or another, they’re obviously adverse to being counted, or even noticed since it may as often mean a bulldozer will come to knock down their shacks. > [@](#): > > But, just as an example, I’ve seen some demographic studies suggesting Cairo (Egypt) may already have 20 million people! Is that true? Who knows. Living here, it’s not hard to credit. After all, there’s a new egyptian born every 24 seconds, and we added an est. 1.35 million last year, according to official stats. > [@](#): > > I don’t know- but I’d hate to be the demographer sifting through Cairo, Calcutta, Sao Paolo or Lagos, trying to find the “real” population. Hell, try to figure out how to provide basic services.