Which one of the following megacities has the highest population?

According to the United Nations World Urbanization Prospects and various demographic studies, Tokyo (Japan) remains the most populous megacity in the world. As of recent estimates, the Greater Tokyo Area has a population of approximately 37 million people, maintaining its top position for several decades.

• Delhi (India) is currently the second-most populous city globally, with a population exceeding 32 million.
• Canton (Guangzhou, China) and Seoul (South Korea) are also among the world's largest urban agglomerations, but their populations (roughly 26 million and 25 million respectively) are significantly lower than Tokyo's.

While Tokyo's population growth has plateaued or slightly declined due to Japan's aging demographic, it still holds the record for the largest urban concentration of humans on Earth.