The Mullapperiyar Dam was constructed by the British,during 1887-1895 across Periyar River in the then Travancore state (now Kerala) territory. The dam's reservoir level is of 152 ft which provides diversion of water from the reservoir through a tunnel to Vaigai basin in Tamil Nadu for irrigation purpose.Apart from providing drinking water to the people of Madurai, Theni, Sivaganga and Ramanathapuram, the diverted waters helpes to irrigate about 80,000 hectares of parched land in these districts.If an earthquake causes the dam to collapse, it can be a threat to the lives of 3.5 million people downstream. The issue needs to be looked at as a national problem, not as a dispute between two states.The diverted water from this dam is used for irrigation in Sivaganga, Madurai and Ramanathapuram districts. The Periyar power station in Tamil Nadu produces hydro-electric power from these waters and distributes that electricity in Tamil Nadu.In 1979, there were few minor earthquakes experienced in the regions surrounding the dam following which safety concerns were raised over the dam. Since then, both states Kerala and Tamil Nadu have been at dispute with each other on the issue.