what is the world's largest city

I think It is Seoul, South Korea, the next will be Sao Paolo, Brazil.

Two of the world's cities, Seoul and Sao Paulo, have official populations of more than tem million people. But probably there are two or trhee more cities that can claim to have reached the 10 million mark in 2003. Bombay, Jakarta, and Karachi, all had populations well in excess of nine million af the end of the 20th century. More information on the website: www.citymayors.com