However, in terms of the city proper Shanghai is the most populous with 13,278,500 inhabitants. It is followed by: Mumbai (Bombay), India (12,622,500); Buenos Aires, Argentina (11,928,400); Moscow, Russia (11,273,400); and Karachi, Pakistan (10,889,100). Tokyo, the most populous urban agglomerate, is 15th with 8,294,200 inhabitants and Mexico City is in 12th place with 8,705,100 inhabitants.

For the total percentage living in urban areas view this statistic.

Over the past 200 years, the number of cities with a population of one million or more has grown from one to over 300.

In 1800, London was the only city in the world with a million people. Now, there are 326 metropolitan areas with populations of one million or higher and 16 with more than 10 million inhabitants. It is estimated that by 2025 there will be 650 cities in the million-plus club. ( http://www.overpopulation.org/human.html)

Prior to the 19th century, cities with more than a million people included Rome at the height of the Roman Empire and the city of Edo, Japan (where Tokyo is today) in the 13th century.

Asia has traditionally had many of the world’s largest cities. In 1990, 44 of the 100 biggest cities in the world were in Asia.

North America and sub-Saharan Africa have most of the new large cities. These are cities that hadn’t been established or were not yet urban centers by the year 1800. ( http://www.peopleandplanet.net/doc.php?id=1088