A five-judge constitution bench of CJI RM Lodha and justices HL Dattu, Chandramauli KR Prasad, Madan B Lokur and MY Eqbal ruled in favour of the Tamil Nadu government that the Kerala government must not restrict the water levels in the Mullaperiyar dam.

The bench said that the Kerala law from 2006 was unconstitutional because it violated the doctrine of separation of powers and interfered with the judiciary, which before the law was passed had ordered to raise the dam's water level, reported the Indian Express and The Hindu.

The Supreme Court has now set up a supervisory committee to oversee the raising of the water levels. [Judgment (PDF 158 pages)]