Abdul Jabbar, an activist who worked for the victims of the Bhopal gas tragedy, died on Thursday at the age of 63, Hindustan Times reported. Jabbar had been undergoing treatment for the past few months.

Earlier in the day, Madhya Pradesh Chief Minister Kamal Nath’s office had said that the state government would bear expenses of Jabbar’s treatment. He was diabetic and was suffering from multiple heart ailments in recent months, reported ThePrint.

Jabbar was the convenor of the Bhopal Gas Peedith Mahila Udyog Sanghathan. He was known for helping victims of the 1984 tragedy, demand compensation and medical relief from the government.

At least 4,000 people were killed in the early hours of December 3, 1984, when 42 tonnes of toxic methyl isocyanate gas leaked from a plant owned by Union Carbide, a subsidiary of Dow Chemical Company, in Bhopal. Thousands more died due to the effects of the gas leak in subsequent years.

Jabbar himself had a respiratory disorder and suffered from vision loss due to the gas leak.