Hundreds of people including MDMK leader Vaiko and CPI leader Nallakkanu were arrested when they were on their way to Sterlite Copper smelter unit to picket it, demanding its closure following alleged noxious gas leak.
The demand for closure gathered momentum after an unspecified gas allegedly leaked from some factories here on March 23, causing mild suffocation, sore throat and eye irritation to several people.
Based on an inspection report by Pollution Control Board, Revenue Divisional Officer K Latha had served a notice on March 24 to the company, dealing in sulphuric acid, directing it to reply by today.
District Collector Ashish Kumar said preliminary investigations indicated release of sulphur dioxide.
Meanwhile, PCB are also taking departmental action in connection with the incident.
There was a scuffle between police and activists of MDMK and CPI and other organisations at Rajaji Park, where they had gathered to demand the plant's closure.
More than 95 per cent of the shops in the town remained closed today. Autorickshaws also did not ply.
Sterlite officials, however, claimed that their plant was safe and the followed the highest safety norms.
