In the world, for classification of urban settlements, mainly the size of population, structure of occupation, administrative structure and essential conditions are considered as the basis.

Following is a brief description of all these basic factors:

1. Size of Population: In order to define urban regions in the world, the basis of population is mainly considered. But variation is found in the size of population for determination of cities in the entire world. Minimum number of people required for a region to be called a city is 250 persons in Denmark, Sweden and Finland, 300 in Iceland, 1000 in Canada and Venezuela, 1500 in Columbia, 2000 in Portugal and Argentina, 2500 in USA and Thailand, 3000 in Japan and 5000 in India.

2. Occupational Structure: Apart from the basis of population, for determination of urban settlement, occupational structure is also considered as the basis. For example, in some countries such as Italy, more than 50% population should be engaged in non agricultural activities. In India, this criteria is 75%. Here, major economic activities have also been considered as a criteria for urban settlements.

3. Administrative Structure: In some countries, administrative structure has been considered as the only criteria to include a settlement under urban settlement. For example, a city is considered to be an urban settlement if it has a municipal corporation, cantonment board and a scheduled urban regional committee. In Brazil and Bolivia, in place of size of population, administrative center is considered a parameter of urban center.

4. Essential Conditions: In the world, urban settlements are also identified on the basis of disposed functions. For example, essential conditions of holiday resorts and tourist places are different from those of industrial areas, port towns and military areas.