Determining the world's largest cities depends on which definitions of "city" and "size" are used, and how those definitions are applied. The "size" of a city can refer to its land area, but it is more typically the population. How one defines the land area of a city is key to determining its population. There are similarities, however, between the cities ranked highest in each of the lists below, most being large metropolises of East Asia or South Asia  such as Karachi, Mumbai, Delhi, Tokyo, Jakarta, Shanghai,Chennai and Seoul.