Hold onto your hats, because the urban landscape as we know it is shifting dramatically! Tokyo, once crowned the world's most populous city, has been dethroned, now sitting in third place behind Jakarta and Dhaka. But here's where it gets controversial: is this just a matter of changing definitions, or does it signal a deeper global transformation? Let’s dive in.
In November 2025, the United Nations dropped a bombshell with its World Urbanization Prospects 2025 report (https://www.un.org/sustainabledevelopment/blog/2025/11/press-release-wup2025/). The findings? Jakarta, Indonesia’s bustling capital, now leads the pack with nearly 42 million residents, followed closely by Dhaka, Bangladesh, with almost 40 million. Tokyo, once the undisputed champion, trails behind with 33 million. But this isn’t just about numbers—it’s about how we define cities and the broader trends reshaping our world.
For decades, Tokyo was synonymous with urban density, its sprawling metropolitan area encompassing prefectures like Kanagawa, Saitama, and Chiba, not to mention Yokohama, Japan’s second-largest city. Yet, Tokyo proper is surprisingly compact, housing just 14 million people. The UN’s new methodology strips away “country-specific city definitions,” giving Jakarta a 30-million-person boost and catapulting it to the top. But is this just statistical sleight of hand, or does it reflect reality?
Here’s the part most people miss: Japan’s population has been shrinking for years due to an aging population, low birth rates, and minimal immigration. In 2025, Japan marked its 16th consecutive year of decline (https://www.iflscience.com/global-population-growth-is-rapidly-declining-heres-why-78166). While Tokyo’s urban population still inches upward, this growth is slowing, and a demographic drop is likely in the coming decades. The UN report notes, “Over the past quarter century, Tokyo’s population has grown more slowly than Jakarta’s and Dhaka’s, dropping it from first place in 2000 to third by 2025.”
This is almost unprecedented in the 21st century. Tokyo and Seoul are the only top-10 cities expected to shrink by mid-century. As other Asian cities boom, Tokyo’s ranking is set to plummet further. By 2050, the UN predicts Tokyo will fall to seventh place, with a population of 30.7 million. Meanwhile, Dhaka and Shanghai are poised to grow at nearly 5% annually, with Dhaka overtaking Jakarta as the world’s largest city and Shanghai rising to third place.
By 2050, the top 10 megacities are projected to look like this:
1. Dhaka (52.1 million)
2. Jakarta (51.8 million)
3. Shanghai (34.9 million)
4. New Delhi (33.9 million)
5. Karachi (32.6 million)
6. Cairo (32.4 million)
7. Tokyo (30.7 million)
8. Guangzhou (29.2 million)
9. Manila (27.1 million)
10. Kolkata (23.8 million)
But here’s the controversial question: Does Tokyo’s decline reflect a failure of Japanese policy, or is it simply the natural ebb and flow of global urbanization? And what does this mean for other aging societies? Let us know your thoughts in the comments!
For a deeper dive, check out the full UN report summary here (https://www.un.org/development/desa/pd/sites/www.un.org.development.desa.pd/files/undesapd2025wup2025summaryofresults.pdf).
