Twenty-five years ago, Bhopal, in Madhya Pradesh, India, earned the unenviable distinction of experiencing the world’s worst ever industrial accident. On 2 December 1984, milky white clouds of poisonous gas escaped from leaking tanks at the Union Carbide pesticide plant, releasing 30 tons of deadly methal isocyanate, which floated over the city’s 1.5 million inhabitants as they slept. Some 3,000 died that night or soon after, with the death toll eventually reaching at least 30,000. Today, 60,000 sufferers are still being treated for eye defects, respiratory ailments and birth deformities.

A tour of the grubby, narrow alleyways around the now-defunct Union Carbide plant site reveals harrowing scenes of hardship. Brothers Vikas, 10, and Aman, 8, sit playing on the step outside their single-roomed home. Neither can walk unaided: their legs are twisted and cannot support them. Their 30-year-old mother says they were born with their deformities because of the effect of the gas attack on her when she was five. She receives no financial benefit for them.