Thousands of survivors of the world's worst industrial accident are protesting for more compensation by blocking the trains in an Indian city. The protests on Saturday were on the 27th anniversary of the disaster in Bhopal, where a Union Carbide pesticide plant leaked lethal gas that killed an estimated 15,000 people and maimed tens of thousands more.

Activist Rachna Dhingra said police charged the protesters with sticks on Saturday in trying to stop them from occupying Bhopal's five train lines, and that three people were admitted to hospital with injuries. The protesters, most of them women sitting on the tracks, in turn threw stones at the police.

Vowing to block trains indefinitely, the five Bhopal victims' rights groups that organised the protest demanded Dow Chemicals, which bought Union Carbide in 2001, pay $US8.1 billion ($7.9 billion) in compensation for more than 500,000 people exposed to the leak.

The protesters - shouting slogans including 'We want compensation' - said India's government accepted far too little in a 1985 settlement for $US470 million, after initially asking for $US3.3 billion.

The Indian government is seeking an additional $US1.7 billion for the victims from Dow, and activists accuse the US company of not cleaning up oil and groundwater contamination in Bhopal. Meanwhile, Dow has maintained the issue was resolved by the $470 million settlement.

'When the moment came to ask for rights for compensation, why this betrayal? The government has undermined the victims,' Dhingra said, calling the official death toll of 5290 for the disaster laughable when the Indian Council of Medical Research was attributing 23,000 deaths up to 2009 to the contamination.

Bhopal activists and survivors are also calling for Dow Chemicals to be dropped as a sponsor of the 2012 London Olympics. On Friday, about 200 protesters marched to the now-abandoned plant and burned effigies of two Olympic officials.

At least 21 Indian Olympic athletes have urged the organisers of the London Games to end Dow's sponsorship, which includes a curtain-style wrap around a stadium where some Olympic events will be held.

India has said it has no plans to skip the Olympics, after the chief minister of Madhya Pradesh state, where Bhopal is located, wrote a letter last month to India's sports minister asking that the country boycott the Games.

London Olympic organisers have said they will not change their position on Dow's sponsorship.

(Sky News, 04/12/2011)