Kolkata is the prime business, commercial and financial hub of eastern India and the main port of communication for the North East Indian states. Kolkata is the third largest economy in India after Mumbai and Delhi. Kolkata, with a GDP (PPP) of $150.1 billion is home to India's oldest, stock exchange company (bourse) – The Calcutta Stock Exchange. Kolkata is home to many industrial units operated by large public- and private-sector corporations; major sectors include Steel, Heavy engineering, Mining, minerals, cement, pharmaceuticals, food processing, agriculture, electronics, textiles, and jute. Economic history and recent developments Kolkata was the capital of the British Indian Empire until 1911. Throughout the British Raj, the city was a major port and commercial center in the world economy. The Partition of India in 1947 was a major blow to the once flourishing economy during the world wars, it removed most of the hinterland, cutting down the supply of the human resource and a took away a huge portion of its market. Also the huge inflow of refugee from East Pakistan was a major drain to the city's infrastructure which was inadequate for the population boom. In the 1970s, the city saw a predominance of the trade-union movements which led the investors to flow out of the state to other newly emerging destinations in India. As the investors lacked trust in the newly formed communist government, the lack of capital destroyed most of its small-scale industries like foundrys and tool casting. Once India's leading city, Kolkata experienced a steady economic decline in the decades following India's independence due to steep population increases and a rise in militant trade-unionism, which included frequent strikes that were backed by left-wing parties. From the 1960s to the late 1990s, several factories were closed and businesses relocated. The lack of capital and resources added to the depressed state of the city's economy and gave rise to an unwelcome sobriquet: the "dying city". There are a few of the oldest and front line banks and PSUs —such as UCO Bank, Allahabad Bank, United Bank of India and Geological Survey of India, Zoological Survey of India, Botanical Survey of India and Tea Board of India—were founded and is headquartered in Kolkata. The oldest operating photographic studio in the world, Bourne & Shepherd, is also based in the city. The Standard Chartered Bank has a major branch in Kolkata. Kolkata is also the headquarters of