1990 Megacities

In 1990, the world’s megacities—urban areas with populations exceeding 10 million—were concentrated primarily in Asia and the Americas, reflecting both historical urbanization and rapid postwar growth. Tokyo was the largest, with over 20 million residents, its expansion fueled by Japan’s economic boom and a long history as the nation’s political and cultural center. New York City, with roots as a colonial port, remained a global financial and cultural hub, while Mexico City’s explosive growth was driven by rural migration and industrialization, making it Latin America’s largest metropolis. São Paulo and Los Angeles also joined the ranks, the former as Brazil’s economic powerhouse and the latter as a sprawling center of entertainment and immigration. In Asia, Shanghai and Beijing were on the cusp of megacity status, while Mumbai (then Bombay) and Kolkata (Calcutta) reflected both colonial legacies and intense rural-to-urban migration. These cities shared trends of rapid population growth, often outpacing infrastructure development, leading to challenges in housing, transportation, and public health. The histories of these megacities reveal a mix of colonial influence, economic opportunity, and demographic shifts, setting the stage for even more dramatic urban expansion in the decades to come.

Data from UN World Urbanization Prospects