The Supreme Court is expected to rule on the Cauvery river water sharing dispute on Friday. Tamil Nadu and Karnataka had moved the court against the 2007 Cauvery Water Disputes Tribunal’s ruling.

In 2007, the tribunal had allocated 419 thousand million cubic feet to Tamil Nadu, 270 tmcft to Karnataka, 30 tmcft to Kerala and 7 tmcft to Puducherry of the 740 tmcft of water available in the Cauvery basin. The Centre had notified the tribunal’s award in 2013.

Tamil Nadu Chief Minister Edappadi Palaniswami has asked the police to be on alert on Friday, keeping in mind the protests and violence in both states because of the dispute in 2017. Karnataka Home Minister Ramalinga Reddy said he was hopeful that the judgment would be in his state’s favour. “However, as we cannot take any chances we have put in place adequate security arrangements in Mysuru, Mandya and Bengaluru districts,” he said, according to the Hindustan Times.

The Cauvery water dispute has been going on for 22 years now.

Here is a timeline of events since 2016:

  • September 5, 2016: The Supreme Court directs Karnataka to release 15,000 cusecs of water from the Cauvery river to Tamil Nadu.
  • September 9, 2016: The top court reduces the quantity of water to 12,000 cusecs, but widespread protests erupt in Karnataka.
  • September 16, 2016: A day-long bandh is held in Tamil Nadu in protest against the violence targeting Tamilians in Karnataka over the water-sharing dispute.
  • September 19, 2016: The Cauvery Supervisory Committee directs Karnataka to release 3,000 cusecs of Cauvery water to Tamil Nadu every day from September 21 to September 30.
  • September 20, 2016: The court revises the figure to 6,000 cusecs, directing Karnataka to release the water to Tamil Nadu every day from September 21 to September 27.
  • September 21, 2016: The Karnataka Cabinet decides to not release water to Tamil Nadu.
  • September 22, 2016: Karnataka Chief Minister Siddaramaiah meets Union Water Resources Minister Uma Bharti in Delhi to explain the state’s difficulty in complying with the Supreme Court order.
  • September 23, 2016: The Karnataka legislature passes a resolution that says they cannot release Cauvery water for anything but drinking water purposes in Bengaluru, and other towns and villages that fall in the river basin.
  • September 26, 2016: The Karnataka government files a petition in the Supreme Court, seeking a modification to its order from September 20.
  • September 27, 2016: The Supreme Court orders the Karnataka government to release 6,000 cusecs of Cauvery water to Tamil Nadu for three days, till the next hearing in the matter on September 29.
  • September 28, 2016: Opposition parties in Karnataka said they were against the Supreme Court’s order to release 6,000 cusecs of Cauvery water to Tamil Nadu at an all-party meeting.
  • October 3, 2016: Karnataka releases 6,000 cusecs of water to the neighbouring state.
  • October 4, 2016: The Supreme Court stays its earlier order to the Centre to set up a Cauvery Water Management Board. It also directs Karnataka to release 2,000 cusecs of water from the river to Tamil Nadu every day from October 7 to 18.
  • October 5, 2016: The Centre sets up a high-level technical team on the court’s instructions to look into the ground reality in the Cauvery river basin. The team finds that both Karnataka and Tamil Nadu face water shortages. It adds that 42 of the 48 taluks in the river basin in Karnataka were drought-affected.
  • October 18, 2016: The Supreme Court once again asks Karnataka to release 2,000 cusecs of Cauvery water per day to Tamil Nadu. The Centre, meanwhile, informs the court that the tribunal’s verdict was final and binding.
  • October 19, 2016: The Supreme Court reserves its order in the Cauvery water-sharing dispute case.
  • July 5, 2017: Tamil Nadu government moves the Supreme Court, accusing the Karnataka government of not providing it its due share of water. It also asks the Centre not to grant any clearance to projects taken up in the Cauvery basin until all issues relating to the sharing of river water is settled.
  • November 24, 2017: The Centre wants to transfer surplus water from Andhra’s Godavari river to the Cauvery. Union minister Nitin Gadkari says the Ministry of Water Resources is working on two-river linking projects to help parched states.
  • January 9, 2018: Supreme Court says it will declare its verdict on the Cauvery water dispute within a month.
  • January 13, 2018: Tamil Nadu Chief Minister Edappadi Palaniswami writes to his Karnataka counterpart, requesting him to release 15 thousand million cubic feet of Cauvery river water to his state to make up for the shortfall in the supply in the 2017-18 irrigation year.
  • January 14, 2018: Karnataka Chief Minister Siddaramaiah says it is not possible to release Cauvery river water to Tamil Nadu.