In March 2019, a river in an industrial town in Johor, Malaysia was poisoned. An illegal dumping of almost three tonnes of toxic waste by a river bank caused the contamination.

More than 4,000 people were hospitalised and required treatment due to the inhalation of toxic fumes. While many suffered mild symptoms of poisoning, some have long-term debilitating ailments that have changed their lives.

We look at what happened and meet the men, women and children who were directly affected by the pollution crisis. Who should be held responsible? How could the tragedy be avoided, or is this the grim reality of living in an industrial town?

From Series 7 of the award-winning series, Undercover Asia