Rank-size rule
Also called: Zipf's law · Topic: Human Settlements and Urbanisation in India · NCERT: Beyond NCERT
Meaning
The rank-size rule says that if a country's cities are ranked by population, the city ranked n has about 1/n of the population of the largest city. So the second city has about half as many people as the first, the third about one-third, and so on. G.K. Zipf stated it in 1949, so it is also called Zipf's law. It describes a balanced city system with a smooth step-down from big to small cities.
Example
Imagine a country whose largest city has 1 crore people. By the rule, its second city would have about 50 lakh, its third about 33 lakh and its fourth about 25 lakh. India's city system roughly follows this pattern, with several large cities and no single giant.
Don't confuse with
- Primate city: one city more than twice the size of the next, such as Bangkok. When a country has a primate city, its cities do not follow the rank-size rule.