NEW DELHI (Reuters) - India’s Supreme Court on Tuesday cleared the way for Vedanta to reopen its south Indian copper smelter by refusing to stay an order from the country’s environmental court.

FILE PHOTO: Police stand gurad outside a copper smelter controlled by London-listed Vedanta Resources in Thoothukudi in the southern state of Tamil Nadu, India, May 28, 2018. REUTERS/Sudarshan Varadhan/File Photo

The government of Tamil Nadu state ordered the smelter shut permanently in May after protests against alleged pollution at the plant in the city of Thoothukudi during which the police killed 13 demonstrators.

Twelve of the 13 protesters were hit by bullets in the head or chest, and half of those were shot from behind, Reuters reported last month.

In December, India’s National Green Tribunal (NGT) revoked the state decision to shut the plant, leading Tamil Nadu to appeal the NGT ruling.

The Supreme Court refused to issue a so-called stay halting the NGT’s decision, but admitted the Tamil Nadu state’s appeal before the high court, allowing that case to proceed.

“The directions that have been passed by the National Green Tribunal by its judgment ... will continue to subsist and will be subject to the ultimate outcome of the appeal,” the supreme court said in its order uploaded on its website.

“As it stands today, the order of the NGT stays and has to be complied with by both the parties,” Vedanta’s counsel Aryama Sundaram said.

Vedanta will now file an application with the Tamil Nadu pollution regulator seeking consent to operate the smelter, said P. Ramnath, the chief executive of Vedanta’s Indian copper business Sterlite Copper which operates the plant.

“It is difficult to say when we will be able to reopen the smelter,” Ramnath said.

Additionally, the Supreme Court issued a stay halting an order by the Madras High Court that barred Vedanta from reopening the Thoothukudi smelter until the Madras court hears a case challenging the NGT’s verdict, said Sundaram.