India's Supreme Court has partially lifted a ban on the mining of iron ore in the southern state of Karnataka.

Last week, the court ordered a halt to all mining in the Bellary district, where roughly 80 percent of the state's iron ore is produced, citing concerns about environmental degradation.

On Friday, the court said state-run NMDC would be the only firm allowed to operate in Bellary and that a maximum of one million tons of iron ore could be extracted a month. None of the ore, which is used to make steel, is allowed to be exported.

Last month, Karnataka's chief minister, B.S. Yeddyurappa, stepped down from his post after he was implicated in a $3.6 million illegal mining scam. The former state leader and 787 other officials are accused of granting mining contracts illegally. Yeddyurappa has denied the allegations.