The definition of urban settlement is, however, a difficult one. Most of the countries define their urban settlements on the basis of a minimum qualifying size of population. The size may vary from country to country and from plain regions to mountainous and desert regions. The criteria of functions, administrative status, layout and amenities are also combined with the criterion of minimum size of population. In Israel, a town, irrespective of its size of population, is a non-agricultural settlement, while in Chile a town is a centre with urban characteristics. The simplest definitions of urban settlement are those which merely go by size, e.
g., in Canada, all settlements with more than 1,000 populations are called urban. In Columbia, the dividing line between rural and urban is 1,500, in Argentina the settlements above 2,000 persons are urban, and in USA urban settlements have more than 2,500 people. In most of the Asian countries such as India, China, Pakistan, Bangladesh, Myanmar, Thailand and Indonesia, villages may be so large that an even greater figure of population has to be qualified.
In Pakistan, all areas having town committees are treated as urban. In UK, a settlement is designated as urban on the basis of local government such as borough, municipal boroughs and urban districts. In India, in the census of 1991, the urban settlements have been defined on the basis of the following criteria: (a) All places with a municipality, corporation, cantonment board or notified town area committee, etc. (b) All other places which satisfy the following criteria: (i) A minimum population of 5,000; (ii) At least 75 per cent of male working population engaged in non-agricultural pursuits, and (iii) A density of population of at least 400 persons per sq. km. In addition, the marginal cases such as project colonies, areas of intensive industrial development, railway colonies, important tourist centers, etc., come in the category of urban. Apart from these, the outgrowths of cities and towns have also been treated as urban.
It may be noticed from the above, that in India, there are two distinct types of urban units: (i) The places which have come into existence by virtue of statutory- notifications and are referred to be the nomenclature adopted in the relevant notifications as Municipal Corporation, municipal board, cantonment board, notified area committee, etc. (ii) The places which are defined as urban because they satisfy criterion (b) above and are referred to as census towns or non-municipal towns. Thus, the definition of an urban centre is highly variable from country to country. In order to make the international data comparable, the United Nations (1958) suggested that the data on urban population should also be presented according to a standardized scale. Consequently, many of the countries have further classified their urban settlements into a number of categories on the basis of population size.
In accordance with this recommendation of the United Nations, the Census of India also classifies the urban places into the following six categories: Class I, those having a population of 100,000 or more; Class II, those having a population between 50,000 and 99,999; Class III, those having a population between 20,000 and 49,999; Class IV, those having a population between 10,000 and 19,999; Class V, those having a population between 5,000 and 9,999 and Class VI, those having a population below 5,000.