Jakarta Ranks World's Largest City as Tokyo Slips to 3rd

Jakarta ranked as the world's largest city with 41.9 million inhabitants followed by Dhaka, while Tokyo slipped to third against the backdrop of population growth in the developing nations and Japan's graying society, a recent U.N. report on urbanization prospects shows.

The population of Japan's capital has grown more slowly than those of Indonesia and Bangladesh, and consequently, its rank among the world's most populous cities descended from first in 2000 to third by 2025, according to the report, which uses an assessment method designed to facilitate international comparisons.

Looking ahead, the Tokyo urban area's population is expected to shrink from 33.4 million in 2025 to 30.7 million in 2050, dropping to seventh in rank as Dhaka takes the top spot with 52.1 million people, followed by Jakarta, Shanghai, New Delhi, Karachi and Cairo.

The term "city" in the report is defined as "any agglomeration of contiguous geographic area" with a density of at least 1,500 inhabitants per square kilometer and a total population of at least 50,000.

Under the methodology used by the U.N. Department of Economic and Social Affairs, which issued the report in November, the total for Tokyo counts only the city's urban areas, together with those of neighboring Saitama, Chiba and Kanagawa prefectures. The official population of Tokyo as a whole is about 14 million.

The estimates are intended to offer data to help policymakers and researchers working to shape urban futures, with the ability to manage city growth sustainably seen as key not only for populations but also for global progress toward climate objectives.

The world has become increasingly urban, with cities now being home to 45 percent of the 8.2 billion people, more than double the proportion in 1950, the report said. Two-thirds of the world's population growth from 2025 to 2050 is projected to occur in cities, with most of the remainder in towns.

While Japan's total population shrank by around 4 million between 2015 and 2025, Tokyo still added over 300,000 people during that period.

In the coming decades, however, an increasing number of countries are projected to experience substantial urban population losses by 2050, the U.N. paper said, citing that Japan and China are among them primarily due to persistently low fertility rates and overall population decline.

Tokyo and Seoul are the only cities among the 10 largest in 2025 that are expected to experience a population decline by mid-century, the report said.