Rajkot is the fourth largest city in the state of Gujarat, India, after Ahmedabad, Surat, and Vadodara. Rajkot is the centre of the Saurashtra region of Gujarat. Rajkot is the 35th-largest urban agglomeration in India, with a population more than 1.2 million as of 2015. Rajkot is the seventh cleanest city of India. Rajkot is also the 22nd-fastest-growing city in the world. The city contains the administrative headquarters of the Rajkot District, 245 km from the state capital Gandhinagar, and 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 from 1 May 1960.