Kolkata (Bengali: কলকাতা), IPA: ['kolkat̪a], formerly Calcutta , is the capital of the Indian state of West Bengal. It is located in eastern India on the east bank of the River Hooghly. The city has a population of almost 4.5 million, with an extended metropolitan population of over 14 million, making it the third-largest urban agglomeration and the fourth-largest city in India. Kolkata served as the capital of India during the British Raj until 1911. Once the centre of modern education, science, culture and politics in India, Kolkata witnessed economic stagnation in the years following India's independence in 1947. However, since the year 2000, an economic rejuvenation has led to a spurt in the city's growth. Like other metropolitan cities of India, Kolkata continues to struggle with urbanisation problems like poverty, pollution and traffic congestion. Kolkata is noted for its revolutionary history, ranging from the Indian struggle for independence to the leftist and trade union movements.