The classification of Indian cities is a ranking system used by the Government of India to allocate House Rent Allowance (HRA) to public servants employed in cities in India. HRA is also used by the Indian Revenue Service (IRS) to provide income tax exemptions. Cities are classified on the basis of their population, as recommended by the Sixth Central Pay Finance. Under the latest HRA city ranking scheme, most popular media and culture considers only tier-X cities to be metropolitan in nature. These eight cities are considered India's "metros".
Under the recommendation of the Sixth Central Pay Commission, the CCA classification was abolished in 2008. The earlier HRA classification of cities was changed from A-1 to X; A, B-1, and B-2 to Y; and C and unclassified cities to Z. X, Y, and Z are more commonly known as Tier-1, Tier-2, and Tier-3 cities, respectively. There are eight X cities and ninety seven Y cities.