Rajkot is the fourth-largest city in the western Indian state of Gujarat, after Ahmedabad, Surat, and Vadodara. It is in the centre of the Saurashtra region of Gujarat. Rajkot is the 35th-largest metropolitan area in India, with a population of more than 2 million as of 2021. Rajkot is the 6th cleanest city of India, and it is the 22nd fastest-growing city in the world as of March 2021. It is located on the banks of the Aji and Nyari rivers. Rajkot was the capital of the Saurashtra State from 15 April 1948 to 31 October 1956, before its merger with Bombay State on 1 November 1956. Rajkot was reincorporated into Gujarat State on 1 May 1960.