Forty years after one of world’s deadliest industrial disasters struck the Indian city of Bhopal, a cleanup operation has finally begun to remove hundreds of tonnes of toxic waste from the site.

However, local campaigners have accused the Indian government of greenwashing, arguing that the 337 tonnes of waste removed this week represents less than 1% of the more than 1m tonnes of hazardous materials left after the disaster and that the cleanup has done nothing to tackle chemical contamination of the area.

There have also been protests over fears that the incineration of the waste will only lead to further contamination and toxic exposure in other areas.

More than 3,000 people were killed in the immediate aftermath and at least 25,000 are estimated to have died overall.

Local groups have claimed the true number is probably even higher due to the long-term effects of the poisonous gas, which include high rates of cancers, kidney and lung diseases. High numbers of babies have been stillborn or born with severe disabilities to gas-affected mothers in recent years.