How can one identify an urban agglomeration ?

Explanation

An urban agglomeration consists of any one of the following three combinations :
(a) a town its adjoining urban outgrowths,
(b) two or more contiguous towns with or without their outgrowths, and
(c ) a city and one or more adjoining towns with their outgrowths together forming a contiguous spread.
Examples of urban outgrowth are railway colonies, university campus, post area, military cantonment, etc. located within the revenue limits of a village or villages contiguous to the town or city.