<P> In 1746, Fort St. George and Madras were captured by the French under General La Bourdonnais, the Governor of Mauritius, who plundered the town and its outlying villages . The British regained control in 1749 through the Treaty of Aix - la - Chapelle and strengthened the town's fortress wall to withstand further attacks from the French and Hyder Ali, the Sultan of Mysore . They resisted a French siege attempt in 1759 under the leadership of Eyre Coote . In 1769 the city was threatened by Mysore and the British were defeated by Hyder Ali, after which the Treaty of Madras ended the war . By the 18th century, the British had conquered most of the region around Tamil Nadu and the northern modern--day states of Andhra Pradesh and Karnataka, establishing the Madras Presidency with Madras as the capital . </P> <P> Gradually, the city grew into a major naval base and became the central administrative centre for the British in South India . With the advent of railways in India in the 19th century, the thriving urban centre was connected to other important cities such as Bombay and Calcutta, promoting increased communication and trade with the hinterland . Sir Arthur Lawley was Governor of Madras from 1906 to 1911 and promoted modern agriculture, industry, railways, education, the arts and more democratic governance . The Governor lived in Government House, Fort St George, and had a country home at Guindy, with access to a golf course, hockey pitches, riding stables and the Guindy Horse Racing Track . In the First World War as Red Cross Commissioner in Mesopotamia, he looked after the welfare of Indian soldiers . Madras was the only Indian city to be attacked by the Central Powers during World War I, when an oil depot was shelled by the German light cruiser SMS Emden on 22 September 1914, as it raided shipping lanes in the Indian Ocean, causing disruption to shipping . </P> <P> After India gained its independence in 1947, the city became the capital of Madras State, which was renamed as Tamil Nadu in 1969 . The violent agitations of 1965 against the compulsory imposition of Hindi and in support of English in India in the state marked a major shift in the political dynamics of the city and eventually it had a big impact on the whole state . Because of Madras and its people, English now exists in India, otherwise Hindi might have been made the sole official language in India . On 17 July 1996, the city known as Madras was officially renamed Chennai, in line with what was then a nationwide trend to using less Anglicised names . On 26 December 2004, an Indian Ocean tsunami lashed the shores of Chennai, killing 206 people in Chennai and permanently altering the coastline . The 2015 Chennai Floods submerged major portions of the city, killing 269 people and resulting in damages of ₹ 86.4 billion (US $1 billion). </P> <P> Chennai is located on the south--eastern coast of India in the north--eastern part of Tamil Nadu on a flat coastal plain known as the Eastern Coastal Plains . Its average elevation is around 6.7 metres (22 ft), and its highest point is 60 m (200 ft). Chennai is 2,184 kilometres (1,357 mi) south of Delhi, 1,337 kilometres (831 mi) southeast of Mumbai, and 345 kilometres (214 mi) east of Bangalore by road . Two major rivers flow through Chennai, the Cooum River (or Koovam) through the centre and the Adyar River to the south . A third river, the Kortalaiyar, travels through the northern fringes of the city before draining into the Bay of Bengal, at Ennore . The estuary of this river is heavily polluted with effluents released by the industries in the region . Adyar and Cooum rivers are heavily polluted with effluents and waste from domestic and commercial sources, the Coumm being so heavily polluted it is regarded as the city's eyesore . A protected estuary on the Adyar forms a natural habitat for several species of birds and animals . The Buckingham Canal, 4 km (2.5 mi) inland, runs parallel to the coast, linking the two rivers . The Otteri Nullah, an east--west stream, runs through north Chennai and meets the Buckingham Canal at Basin Bridge . Several lakes of varying size are located on the western fringes of the city . Some areas of the city have the problem of excess iron content in groundwater . </P>

When was the name madras changed to chennai