HUNDREDS of survivors of the Bhopal gas leak and their supporters took to the streets of the Indian city today to mark the 30th anniversary of the world's worst industrial disaster.

The protesters demanded harsher punishments for those responsible and suitable compensation for the victims of the tragedy.

On the morning of December 3 1984 a pesticide plant run by Union Carbide leaked about 40 tons of deadly methyl isocyanate gas into the air of Bhopal, quickly killing about 4,000 people.

Lingering effects of the poison pushed the death toll to about 15,000 over the next few years, according to government estimates.

In all, at least 500,000 people were affected and, 30 years later, thousands of children are still born with brain damage, missing palates and twisted limbs because of their parents' exposure to contaminated gas or water.

The disaster remains an open wound in India, where many consider Union Carbide's £300 million settlement a gross insult.

Survivor Ram Pyari said the tragedy still haunts her.

"Everything was destroyed," she said.

"My sons and my daughter-in-law died, my leg was amputated. I have to drag myself.

"These killers did not heed anything.

"Why are they not brought to court?

"Why are they not hanged?"

In the poor neighbourhoods behind the Union Carbide plant, where the worst of the tragedy unfolded, survivors and their relatives and supporters burned effigies of Warren Anderson, who headed Union Carbide Corporation at the time of the leak, and a banner emblazoned with the logo of Dow Chemicals, which subsequently bought Union Carbide.

Mr Anderson died in September in a Florida nursing home.

Following the disaster, he fled India while on bail and never returned.

In 2011 the Indian government made a renewed push to extradite Mr Anderson, then 90, from the US, without success.

Prosecutors had intended to try him on culpable-homicide charges.

The survivors say that he remains a symbol of the lack of accountability of big multinational corporations.

Dow Chemical now insists that it has no liability because it bought Union Carbide after the cases had been settled.