Kolkata, also known as Calcuttathe official name until 2001) is the capital of the Indian state of West Bengal. According to the 2011 Indian census, it is the seventh most populous city; the city had a population of 4.5 million, while the suburb population brought the total to 14.1 million, making it the third-most populous metropolitan area in India. Kolkata Megalopolis is the area surrounding Kolkata Metropolitan city with additional population. Located on the east bank of the Hooghly River approximately 80 kilometres (50 mi) west of the border with Bangladesh, it is the principal commercial, cultural, and educational centre of East India, while the Port of Kolkata is India's oldest operating port and its sole major riverine port. The city is widely regarded as the "cultural capital" of India, and is also nicknamed the "City of Joy". Recent estimates of Kolkata Metropolitan Area's economy have ranged from $60 to $150 billion (GDP adjusted for purchasing power parity) making it third most-productive metropolitan area in India, after Mumbai and Delhi.