Other lists I've seen count that 28 mm figure as Tokyo/Yokohama, sprawling outside the city proper. This list of top ten most populous *urban areas* (the city proper) puts Tokyo at #10:\n\n1. Seoul 10.2 million \n2. Sao Paulo 10 million\n3. Mumbai 9.9 million\n4. Jakarta 9.37 million\n5. Karachi 9.3 million\n6. Moscow 8.29 million\n7. Istanbul 8.26 million\n8. Mexico City 8.23 million\n9. Shanghai 8.2 million\n10. Tokyo 8.1 million
What is  the largest city in the world?