In India, the word “urban agglomeration” is defined in the Census of India – which provides statistical information on different characteristics of the people of India. The responsibility of conducting the decennial Census rests with the Office of the Registrar General and Census Commissioner, India under Ministry of Home Affairs, Government of India. (The 2011 census report may be seen here.)
An urban agglomeration is a continuous urban spread constituting a town and its adjoining outgrowths (OGs), or two or more physically contiguous towns together with or without outgrowths of such towns. An Urban Agglomeration must consist of at least a statutory town(all places with a municipality, corporation, cantonment board or notified town area committee, etc.) and its total population (i.e. all the constituents put together) should not be less than 20,000 as per the previous Census.
Examples: Greater Mumbai UA, Delhi UA, etc.
With these two basic criteria having been met, the following are the possible different situations in which Urban Agglomerations would be constituted: (i) a city or town with one or more contiguous outgrowths; (ii) two or more adjoining towns with their outgrowths; and (iii) a city and one or more adjoining towns with their outgrowths all of which form a continuous spread. In varying local conditions, there were similar other combinations which have been treated as urban agglomerations satisfying the basic condition of contiguity.
Here each such individual area by itself may not satisfy the minimum population limit to qualify it to be treated as an independent urban unit but may deserve to be clubbed with the town as a continuous urban spread.
An Out Growth (OG) is a viable unit such as a village or a hamlet or an enumeration block made up of such village or hamlet and clearly identifiable in terms of its boundaries and location. Some of the examples are railway colony, university campus, port area, military camps, etc., which have come up near a statutory town outside its statutory limits but within the revenue limits of a village or villages contiguous to the town.
While determining the outgrowth of a town, it is ensured that it possesses the urban features in terms of infrastructure and amenities such as pucca roads, electricity, taps, drainage system for disposal of waste water etc. educational institutions, post offices, medical facilities, banks etc. and physically contiguous with the core town of the UA.
Examples: Central Railway Colony (OG), Triveni Nagar (N.E.C.S.W.) (OG), etc.
Each such town together with its outgrowth(s) is treated as an integrated urban area and is designated as an ‘urban agglomeration’.
A similar definition used by United Nation is called Urban sprawl which refers to expansion of an urban area to accommodate its growing population.
In the 2011 Census, 475 places with 981 OGs have been identified as Urban Agglomerations as against 384 UAs with 962 OGs in 2001 Census.
A predecessor of the term “Urban Agglomeration” is a term called “standard urban area”. This was a new concept developed for the 1971 Census for the tabulation of certain urban data. The essential criteria of a Standard Urban Area are:
- it should have a core town of a minimum population size of 50,000,
- the contiguous areas made up of other urban as well as rural administrative units should have close mutual socio- economic links with the core town and
- the probabilities are that this entire area will get fully urbanised in a period of two to three decades.
The idea is that it should be possible to provide comparable data for a definite area of urbanisation continuously for three decades which would give a meaningful picture. This replaced the concepts of Town Group that was in vogue at the 1961 Census. The town group was made up of independent urban units not necessarily contiguous to one another but were to some extent inter-dependent. The data for such town groups became incomparable from census to census as the boundaries of the towns themselves changed and the intermediate areas were left out of account; this concept came for criticism at one of the symposium of the International Geographic Union in Nov.-Dec.1968 and the concept of Standard Urban Area came to be developed for adoption at the 1971 Census.