"Metropolitan Cities of India"(PDF). Central Pollution Control Board. National Informatics Centre. p. 3. Archived from the original(PDF) on 23 September 2015. Retrieved 28 July 2014.
"Metropolitan Cities of India"(PDF). Central Pollution Control Board. National Informatics Centre. p. 3. Archived from the original(PDF) on 23 September 2015. Retrieved 28 July 2014.