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.The Pallavas of Kanchi built the areas of Mahabalipuram and Pallavaram during the reign of Mahendravarman I.
Sculpted caves and paintings have been identified from that period.
Ancient coins dating to around 500 BC have also been unearthed from the city and its surrounding areas.
There are also suggestions that it may have originated from the Portuguese phrase Mãe de Deus or Madre de Dios, which means "mother of God", due to Portuguese influence on the port city, specifically referring to a Church of St. Stone age implements have been found near Pallavaram in Chennai.
According to the Archaeological Survey of India (ASI), Pallavaram was a megalithic cultural establishment, and pre-historic communities resided in the settlement.
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.பெண்களுக்காகவும், இட ஒதுக்கீட்டுக்காகவும் போராட்டம் நடத்தும் தி.மு.க. உள்ளிட்ட கட்சிகள் காஷ்மீரில் பெண்கள், பிற்படுத்தப்பட்ட மக்களுக்கு கிடைக்கும் சலுகைகளை எதிர்ப்பதாக பா.ஜ.க. the official name until 1996) is the capital of the Indian state of Tamil Nadu.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.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.The region around Chennai has served as an important administrative, military, and economic centre for many centuries.