What is mean by Urban Agglomeration (UA)?
Urban Agglomeration (UA) : 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 and its total population (i.e. all the constituents put together) should not be less than 20,000 as per the 2001 Census. In varying local conditions, there were similar other combinations which have been treated as urban agglomerations satisfying the basic condition of contiguity.
Examples: Greater Mumbai UA, Delhi UA, etc.
Towns: For the Census of India 2011, the definition of urban area is as follows;
1. All places with a municipality, corporation, cantonment board or notified town area committee, etc.
2. All other places which satisfied the following criteria:
i) A minimum population of 5,000;
ii) At least 75 per cent of the male main working population engaged in non-agricultural pursuits; and
iii) A density of population of at least 400 persons per sq. km.
The first category of urban units is known as Statutory Towns. These towns are notified under law by the concerned State/UT Government and have
local bodies like municipal corporations, municipalities, municipal committees, etc., irrespective of their demographic characteristics as reckoned on 31st December 2009. Examples: Vadodara (M Corp.), Shimla (M Corp.) etc.
The second category of Towns (as in item 2 above) is known as Census Town. These were identified on the basis of Census 2001 data.
Population of UAs/Towns:
1. The total urban population in the country as per Census 2011 is more than 377 million constituting 31.16% of the total population.
2. Class I UAs/Towns: The UAs/Towns are grouped on the basis their population in Census. The UAs/Towns which have at least 1,00,000 persons as population are categorised as Class I UA/Town. At the Census 2011, there are 468 such UAs/Towns. The corresponding number in Census 2001 was 394.
3. 264.9 million persons, constituting 70% of the total urban population, live in these Class I UAs/Towns. The proportion has increased considerable over the last Census. In the remaining classes of towns the growth has been nominal.
4. Million Plus UAs/Towns: Out of 468 UAs/Towns belonging to Class I category, 53 UAs/Towns each has a population of one million or above each. Known as Million Plus UAs/Cities, these are the major urban centres in the country. 160.7 million persons (or 42.6% of the urban population) live in these Million Plus UAs/Cities. 18 new UAs/Towns have been added to this list since the last Census.
5. Mega Cities: Among the Million Plus UAs/Cities, there are three very large UAs with more than 10 million persons in the country, known as Mega Cities. These are Greater Mumbai UA (18.4 million), Delhi UA (16.3 million) and Kolkata UA (14.1 million). The largest UA in the country is Greater Mumbai UA followed by Delhi UA. Kolkata UA which held the second rank in Census 2001 has been replaced by Delhi UA. The growth in population in the Mega Cities has slowed down considerably during the last decade. Greater Mumbai UA, which had witnessed 30.47% growth in population during 1991-2001 has recorded 12.05% during 2001-2011. Similarly Delhi UA (from 52.24% to 26.69% in 2001-2011) and Kolkata UA (from 19.60% to 6.87% in 2001-2011) have also slowed down considerably.