Tokyo is the largest city in the world by a wide margin. The metropolitan area population of Tokyo is 32.45 million which is approximately 12 million more people than the second largest city, Seoul. If Tokyo was its own nation, it would be the 38th largest in the world--larger than Morocco, Iraq, Nepal, and Peru. Tokyo is approximately the size of New York City and London--combined. It's very big.
The twenty largest cities in the world are listed below. China is home to three of them but its largest, Shanghai is only number 10. India has three of the top twenty as well--Mumbai (5), Delhi (8), and Kolkata (14). Japan and the United States also have two each. Asia hosts 13, North America 3, South America 2, Africa 1, and Europe 1. Eleven serve as capital cities for their nations. Only three cities lie south of the equator--Jakarta (6), Sao Paulo (7), and Buenos Aires (17). Interestingly, the population of New York City (4) is greater than that of the entire state of New York because the metropolitan area extends into both Connecticut and New Jersey.
City Population (Metropolitan Area)
1. Tokyo, Japan 32.45 M2. Seoul, South Korea 20.55 M
3. Mexico City, Mexico 20.45 M
4. New York City, USA 19.75 M
5. Mumbai, India 19.20 M
6. Jakarta, Indonesia 18.90 M
7. Sao Paulo, Brazil 18.85 M
8. Delhi, India 18.60 M
9. Osaka-Kobe-Kyoto, Japan 17.38 M
10. Shanghai, China 16.65 M
11. Manila, Phillipines 16.30 M
12. Hong Kong-Shenzhen, China 15.80 M
13. Los Angeles, USA 15.25 M
14. Kolkata, India 15.10 M
15. Moscow, Russia 15.00 M
16. Cairo, Egypt 14.45 M
17. Buenos Aires, Argentina 13.18 M
18. London, UK 12.89 M
19. Beijing, China 12.50 M
20. Karachi, Pakistan 11.80 M
[Source: wikipedia.org]