Megacity Populations 1950 to 2100
The history of megacities—urban areas with populations exceeding 10 million—reflects the dramatic transformation of human settlement patterns over the past two centuries. For most of history, cities were relatively small by modern standards. Ancient cities like Rome, Alexandria, and Chang’an (Xi’an) rarely surpassed a population of one million, constrained by technological, agricultural, and transportation limits.
The Industrial Revolution in the 19th century marked a turning point. Advances in agriculture, industry, and transportation allowed cities to grow rapidly, both in population and physical size. London became the world’s first true megacity by the late 1800s, its population swelling past 6 million by 1900. New York City soon followed, driven by waves of immigration and economic opportunity. By the mid-20th century, Tokyo, Shanghai, and other cities in Asia began to experience explosive growth, fueled by postwar reconstruction and rural-to-urban migration.
Population trends in megacities have shifted dramatically since the 1950s. In 1950, only New York and Tokyo qualified as megacities. By 1975, there were three. However, the late 20th and early 21st centuries saw a rapid acceleration, especially in the developing world. By 2020, there were over 30 megacities globally, with the majority located in Asia, such as Delhi, Shanghai, and Jakarta, as well as in Africa and Latin America, including Lagos, Cairo, São Paulo, and Mexico City. These cities often face significant challenges related to infrastructure, housing, pollution, and social inequality, but they are also engines of economic growth and cultural dynamism.
The rise of megacities reflects broader global trends: urbanization, population growth, and economic transformation. Today, more than half of the world’s population lives in urban areas, and projections suggest that by 2050, nearly 70% will reside in cities, with the number and size of megacities continuing to grow. The history of megacities is thus not just about population numbers, but about the evolving relationship between people, technology, and the urban environment.