This is a very complicated problem almost for two decades this problem was in supreme court. If you want to know the whole scene of this problem, you should look in its history. This dispute had started in 19th century, actually the dispute has its origin in that time when there are Kings and emperors of each region, these Kings use to show their power and tend to make happy their people in fact you all know how these Kings used their power to gain support of its population. The dispute is between four constituencies or you can say that majorily this dispute is between two constituencies that is karnataka and tamilnadu over the share of water. This dispute was very controversial as there was some instances of violence in the states. The sc of India had previously constituted a tribunal to look into this matter. The tamilnadu side said in its favour that it has developed very large amount of land on which agriculture can be done so it needs much water for their arable land. The karnataka side said that there has not enough water for the residents of bengaluru so it needs extra water. In today's decision supreme court has ruled out that karnataka's part of water should be increased because water is basic necessity for the survival of any living being. Karnataka has welcomed the order but tamilnadu has criticised, the reason you all know. All of us know the fact that bengaluru is it hub of our country, in absence of potable water the sector could not grow. It is a welcoming decision of the court.
The supreme court has constituted a tribunal to look over the matter and implement its order.