The protests turned violent with agitators fighting pitched battles with police, prompting it to open fire.
On Tuesday, Sterlite Copper in a statement said: "It's with great sorrow and regret that we witnessed today's incidents around the protest today at Tuticorin". Palaniswami, however, defended the police action and said that the circumstances forced police to take the extreme step.
Almost 5,000 people demanding closure of the Vedanta group-owned plant went on the rampage over pollution concerns, clashing with police, and setting vehicles and public property on fire.
Making it clear that the process should be completed before September 23, the judges said that Vedanta should cease the construction of the unit till then. Environmental activists say the cooper plant is polluting local water resources, allegations the company denied as "false propaganda". The protests escalated after the company announced the expansion of the unit.
The Opposition Dravida Munnetra Kazhagam (DMK) came out strongly against the killings of protesters in police firing and compared the incident with Punjab's Jallianwalla Bagh massacre by the British, which took place almost a hundred years ago.
In March the Madras High Court ordered the police to provide adequate security to the pant and its employees
Thousands of protestors assembled for hours in India's southern Tamil Nadu to demand the closure of a British-owned copper plant due to worries over pollution, Agence France-Presse reports. That's because of the inefficiency of the government.
Chief Opposition party in Tamil Nadu, the DMK has compared the deaths to the Jallianwallah Bagh Massacre.
"On an overall reading of the pamphlets as well as taking into consideration of the various disturbances and untoward incidents happening in and around the petitioner factory, the proposed protest is likely to trigger a law and order situation and in this scenario, invoking section 144 of Cr.P.C would be highly recommended in public interest".
Congress president Rahul Gandhi on Tuesday termed the death of protesters a "brutal example of state sponsored terrorism". These citizens were murdered for protesting against injustice.
Meanwhile, actor-turned-politician Kamal Haasan is heading to Tuticorin.