9 Cities With More Than 20 Million People

The population of Beijing, China’s capital city, has been increasing rapidly since the mid-20th century, showing an average growth rate of about 20% per decade. Between 2000 and 2010 alone, the number of Beijing residents grew by 44% — and some authorities have estimated that the city’s population will reach 50 million by 2050.

Mumbai — formerly known as Bombay — is India’s largest city by population, though Delhi (see No. 2) boasts the largest metropolitan area. The country’s most densely populated city, Mumbai, also India’s business capital, has seen its population more than double since 1991 — in large part due to the continuing arrival of job-seekers from other parts of the sub-continent.

The largest city in Egypt (second-place Alexandria has a mere 30% of its population) and the nation’s capital, Cairo, which is more than 2,000 years old, is also the most populous metropolis on the African continent and in the Arab world.

The capital of Bangladesh and also its main economic and cultural center, Dhaka (sometimes spelled Dacca) is the sixth-most densely populated city in the world. It has about six times as many residents today as it did in 1950.

The Mexican capital is not only the second-largest city in the Americas (after São Paulo; see No. 4), but also home to more Spanish-speakers than any other city in the world. Its greater metropolitan area is comprised of 61 municipalities, two of which have populations of more than a million themselves.

The largest city in Brazil and in the Americas as a whole — and also by far the largest Portuguese-speaking city — São Paulo had a population of only 2,334,038 in 1950, about one tenth of the current number. In addition to native Brazilians, it has benefited economically, socially, and culturally from a large influx over the past century or so of immigrants from Europe and Asia.

China’s largest city, Shanghai is also one of the world’s fastest growing ones, increasing by double-digits in almost every year since 1992. A major financial capital, it has long drawn people from other parts of the country, and long-term migrant workers are said to represent almost 40% of the city’s population.

The urban agglomeration of Delhi, which incorporates the Indian capital, New Delhi, is one of the world’s fastest growing cities, and the largest in India in both population and area. That population has increased by almost 900,000 since 2015 alone, reflecting both natural growth and immigration.

The world’s most populous city, Tokyo has seen its population more than triple since 1950. However, it has shrunk slightly since 2015, to the tune of 0.14%. Today home to about a quarter of the country’s population, Tokyo has always been Japan’s largest city. In the 18th century, when it was still known by its old name of Edo, it became the first Asian city whose population exceeded a million.