The Madras High Court said the copper smelting plant had been "letting out effluents into air and water which is having a devastating impact".

BBC: India court orders Vedanta subsidiary plant to close

Dioxin, though, is usually formed as a byproduct in processes such as copper smelting, paper-production and the making of pesticides and chlorine-containing organic chemicals.

CNN: THE GREAT DIOXIN SCARE

In September 2010, the Madras High Court had ordered the copper smelting plant to shut down saying it was "letting out effluents into air and water which is having a devastating impact".

BBC: Sterlite Industries plant

They want to provide a series of incentives to mine owners and firms which make gold as a by-product of smelting copper ore.

BBC: Golden opportunity for old Indian mines