What defines a megacity?

A megacity is defined as a city with a population of over 10 million people. This definition is used by various organizations and studies to categorize cities that have reached this significant population threshold. Megacities are typically characterized by their large urban areas, economic influence, and social dynamics that come from having such a dense population. They often face unique challenges related to infrastructure, urban planning, housing, and providing services to their residents.

The population threshold of 10 million is important because it marks a significant shift in urbanization patterns and is often associated with rapid industrialization and migration into urban centers. Cities of this size tend to be influential not just in their own countries but can also impact global economics and culture.

Other options do not accurately capture the essence of what defines a megacity. For instance, a population of over 5 million may categorize a large city but does not reach the megacity threshold. Similarly, the size measured in square miles and the status of being a capital city do not inherently relate to population size but rather geography, governance, or administrative significance. Therefore, the classification based on population over 10 million is the most accurate for identifying megacities.