A three-member panel formed to look into the closure of the Sterlite copper plant in Tamil Nadu’s Thoothukudi on Wednesday said that the state’s decision to shut down the plant is “not sustainable”. Justice Tarun Agarwal, the chairperson of the panel, said the All India Anna Dravida Munnetra Kazhagam government’s decision was against the principles of natural justice.

However, the committee asked Vedanta, the firm which owns the plant, to set rules for how waste management is to be carried out. It also asked the Central Pollution Control Board to ensure that Vedanta complies with pollution norms.

The panel had submitted its report on the closure of the plant to the National Green Tribunal on Tuesday, The News Minute reported.

On October 29, the Tamil Nadu government had told the National Green Tribunal, which is hearing a petition filed by Vedanta to reopen the plant, that air quality in Thoothukudi has improved since it was shut down in May. Senior counsel CS Vaidyanathan, appearing for the state government, submitted data collected by the Tamil Nadu Pollution Control Board showing reduced levels of sulphur dioxide and other chemicals in the ambient air near the plant. Vedanta contested this claim.

The Tamil Nadu Pollution Control Board submitted a comparative study of air quality to the three-member panel showing the change in levels of sulphur dioxide before and after the plant was shut down. Fathima Babu and Thermal S Raja, who are intervenors in the matter, said the pollution control board’s data showed an improvement in the ambient air quality in the neighbourhood.

On April 9, the pollution control board had rejected the plant’s application to renew its licence to operate beyond March 31, 2018.

Thirteen people agitating against the expansion of the smelter were killed in police firing on May 22 and May 23, prompting the state government to permanently shut down the plant on May 28.

The counsel for Babu and Raja on Wednesday asked the panel for more time to file their responses. The committee posted the matter for hearing next on December 7.