Kolkata is the capital of the Indian state of West Bengal. Located on the east bank of the Hooghly River, it is the principal commercial, cultural, and educational center of East India, while the Port of Kolkata is India's oldest operating port and its sole major riverine port. In 2011, the city had a population of 4.5 million, while the population of the city and its suburbs was 14.1 million, making it the third-most populous metropolitan area in India. 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.