The sharing of waters of the Kaveri river has been the source of a serious conflict between the Indian states of Tamil Nadu and Karnataka. The genesis of this conflict rests in two agreements in 1892 and 1924 between the erstwhile Madras Presidency and Princely State of Mysore. The 802 kilometres (498 mi) Kaveri river has 44,000 km2 basin area in Tamil Nadu and 32,000 km2 basin area in Karnataka. Karnataka contends that it does not receive its due share of water from the river. It claims that the agreements were skewed heavily in favour of the Madras Presidency, and has demanded a renegotiated settlement based on “equitable sharing of the waters”. Tamil Nadu, on the other hand, pleads that it has already developed almost 3,000,000 acres (12,000 km2) of land and as a result has come to depend very heavily on the existing pattern of usage. Any change in this pattern, it says, will adversely affect the livelihood of millions of farmers in the state.
Decades of negotiations between the parties bore no fruit. The Government of India then constituted a tribunal in 1990 to look into the matter. After hearing arguments of all the parties involved for the next 16 years, the tribunal delivered its final verdict on 5 February 2007. In its verdict, the tribunal allocated 419 TMC of water annually to Tamil Nadu and 270 TMC to Karnataka; 30 TMC of Kaveri river water to Kerala and 7 TMC to Puducherry. Karnataka and Tamil Nadu being the major shareholders, Karnataka was ordered to release 192 TMC of water to Tamil Nadu in a normal year from June to May. The dispute however, did not end there, as all four states decided to file review petitions seeking clarifications and possible renegotiation of the order.
On 5 September 2016, in the latest development in Cauvery river water controversy, Supreme Court directed the Karnataka government to release 15,000 cusecs of water per day to Tamil Nadu for the next ten days. On 12 September, the Supreme Court modified its order, and instead asked the state administration in Karnataka to release 12,000 cusecs of water on a daily basis till September 20. Widespread disorder was present in Karnataka with bandhs, road, rail, metro and air travel impacted, buses burnt, and anti-tamil violence resulting in curfew being imposed in parts of Bengaluru.