At least 11 people have been killed after chemical gas leaked from an industrial plant in southern India, leaving people struggling to breathe and collapsing in the streets as they tried to flee.

The dead included an eight-year-old girl, and nearly 1,000 people suffered breathing difficulties and other reactions in the incident in Vishakhapatnam, Andhra Pradesh state.

The synthetic chemical styrene leaked from the LG Polymers plant in the city on India’s Bay of Bengal coast while workers were preparing to restart the plant after the coronavirus lockdown was eased, administrator Vinay Chand said.

A fire that broke out before the gas leak has been extinguished, and police said the leak was later stopped and the air had cleared.

Mr Chand said several people fainted on the road and were taken to hospital.

Nearly 100 people are in hospital in non-life-threatening condition, Police Commissioner RK Meena said.

He said one person died falling into a well while running away and another died after he jumped from the second storey of his house to escape.

South Korean company LG Chem operates the plant, and said it is co-operating with Indian authorities to help residents and employees.

LG Chem is looking into what caused the leak of the gas, which is used for producing plastic, company official Song Chun-seob said.

It employs around 300 workers at the Vishakhapatnam plant.

Casualties are taken for medical treatment
Casualties are taken for medical treatment (AP)

Nearly 1,000 people in an area of two miles complained of breathing difficulties and burning sensation in their eyes, Mr Chand said.

Authorities deployed 25 ambulances to take the sick to hospitals and others away from the accident site.

Mr Meena said nearly 3,000 people were evacuated from a village near the plant.

Images from television showed people lying in the streets after they had collapsed while trying to flee.

A witness said there was total panic as a mist-like gas enveloped the area. “People felt breathless in their homes and tried to run away. Darkness added to the confusion,” he told a television channel.

Srijana Gummala, the local municipal commissioner, said water was sprayed in the area to minimise the impact of the gas. “Through public address system, the people are being asked to use wet masks,” he said.

India imposed a strict nationwide lockdown on March 25 to control the spread of coronavirus. Measures were eased on Monday, allowing neighbourhood shops and manufacturing units to reopen to resume economic activity.

India has so far reported nearly 50,000 virus cases with 14,183 recovered and 1,694 deaths.