Countries and megacities

In 2025, India and China were the only countries with populations above one billion; UN estimates put them at about 1.46 and 1.42 billion, respectively. The second part of the supplied claim is outdated: under the UN’s harmonized 2025 method, nine of the ten most populous cities are in Asia; Cairo is the only exception. Rankings depend on what counts as a “city.” The UN used DEGURBA, which groups dense urban areas using common criteria rather than relying solely on administrative boundaries.