Mullaperiyar, in Kerala's Idukki district, was constructed in 1895 by the king of Travancore under an accord with the British government.
Under the accord, the 8,000-acre dam area was leased to Madras presidency (which later became Tamil Nadu) for 999 years. The accord mandated that the water from the dam would be supplied for drinking and irrigation.
The dam is vital for people living in the drought-prone districts of Theni, Dindigul, Madurai, Sivagangai and Ramanathapuram of Tamil Nadu. It irrigates about 220,000 acres and supplies drinking water to Madurai city and several towns.
Kerala, which was formed in 1956 from Madras, has for the past three decades been complaining that the dam built with old technology and material is unsafe and can collapse, endangering the lives of 3.5 million people in five districts.
Image: An undated picture showing a view of the Mullaperiyar dam in Idukki district, Kerala (Photo credit: Rameshng at ml.wikipedia/ Licensed under Wikimedia Commons)