Tokyo Overtaken as World’s Biggest City: 2025 Urban Population Trends and Future Projections

The United Nations’ recent report on megacities reveals a landmark shift in global urban population rankings, with Jakarta now recognized as the world’s largest city by population, overtaking Tokyo, which has fallen to third place. Jakarta’s population has surged to 41.9 million in 2025, surpassing Tokyo’s relatively stable 33.4 million residents. Bangladesh’s Dhaka has climbed to second place with 36.6 million inhabitants and is forecasted to become the largest city globally by 2050. Meanwhile, London is projected to witness marked population growth by 2050, indicating significant urban expansion beyond Asia.

Data-Backed Comparison of Tokyo, Jakarta, Dhaka, and London Populations
Tokyo, once the world’s most populous city since 2000, now ranks third after Jakarta and Dhaka. Jakarta’s extraordinary growth reflects an increase from a previous second-place rank to 41.9 million residents, fueled by rapid urbanization in Indonesia. Dhaka’s population has climbed dramatically from ninth to second place, now housing 36.6 million people, and is projected to hit approximately 52.1 million by 2050. Tokyo, with around 33.4 million, shows a stable or slightly declining population due to demographic challenges, including an aging population. In contrast, London’s population is expected to grow by over 21% by 2050, adding roughly 570,000 residents, reinforcing its role as a global urban center outside Asia.

Future Urban Projections and Implications for Urban Planning
The UN report highlights a dramatic rise in the number of megacities, now totaling 33 worldwide, with 19 in Asia alone. Dhaka is forecast to surpass all others by mid-century, emphasizing urgent needs for sustainable urban planning to manage infrastructure, housing, and resources efficiently. Jakarta faces mounting challenges from climate change, notably rising sea levels threatening up to a quarter of the city by 2050, prompting Indonesia to construct a new capital city, Nusantara. London’s population growth signals increasing demands on real estate, transportation, and public services. These projections underline the critical importance of integrated urban and rural planning to balance growth sustainably.

Environmental and Socio-Economic Drivers of Urban Population Shifts
Jakarta and Dhaka’s rapid expansions are driven by rural-to-urban migration as residents seek economic opportunities amid environmental pressures like flooding and climate change. Dhaka’s growth is further propelled by migrants fleeing adverse effects of rising sea levels. Tokyo’s plateaued or declining population stems from its aging demographic and slower birth rates, reflecting socio-economic stability but also demographic challenges. Jakarta’s growth also brings socio-economic inequalities, with low-income residents increasingly vulnerable, as reflected in recent protests. London’s growth is tied to economic opportunities and international migration, posing different sustainability challenges compared to megacities in Asia.

Sustainable Urban Growth Challenges in Megacities
The UN emphasizes the rising complexity of managing sustainable development in megacities due to rapid population growth, environmental risks, and socio-economic disparities. Challenges include housing affordability, infrastructure strain, climate vulnerability, and governance complexities. Integrated policies aligning land use, mobility, and public services are crucial for sustaining urban growth. Countries face balancing rapid urbanization with environmental stewardship to mitigate flooding, pollution, and resource scarcity. The case of Jakarta’s planned new capital exemplifies proactive governance addressing these challenges. Globally, the rise in megacity numbers highlights the pressing need for sustainable urban frameworks embracing technological innovations and equitable development.

This transformative urban landscape marks a pivotal moment in global city rankings, underscoring the vital need for sustainable planning as megacities like Jakarta, Dhaka, and London expand dramatically by 2050, while traditional giants like Tokyo navigate demographic shifts and stability challenges.