BANGALORE - All five people who died of Covid-19 in Bhopal, the capital of Madhya Pradesh, are confirmed to be victims of a toxic gas leak in the city in 1984. They were all suffering from respiratory illnesses that made them more vulnerable to the disease.

More than 500,000 people had been exposed to poisonous gas from the leak at the pesticide factory of Union Carbide, now owned by the American DowDuPont.

About 4,000 people died, and around 350,000 survivors are registered for state-subsidised treatment for the long-term effects of the gas leak. The factory site in Bhopal remains contaminated.

The Madhya Pradesh government converted the only hospital that treated the gas leak victims - the Bhopal Memorial Hospital And Research Centre (BMHRC) - into a Covid-19 care hospital. It admitted few Covid-19 patients, but for 23 days, gas leak victims have been turned away.

The World Health Organisation says that people with cardio-vascular and pulmonary issues, diabetes, cancer and compromised immune systems are at greater risk of being infected by the coronavirus, becoming critically ill and dying due to Covid-19.

"Gas leak survivors have weak immune systems, cancer or respiratory issues. But the government just didn't make the connection," said Ms Rachna Dhingra, a social activist.

The first person in Bhopal to die of Covid-19, 55-year-old Naresh Khatik, had been suffering from chronic pulmonary disease since the gas exposure.

He had felt breathless on April 2, but since the state facility was closed, his son said he went to a private hospital. He died on April 5, while on a ventilator, and tested positive for Covid-19.

An 80-year-old survivor with chronic respiratory issues was refused treatment by three hospitals, a 40-year-old oral cancer patient died on the way to hospital, and another with a history of tuberculosis tested positive but died walking to the Covid-19 ward. A 75-year-old journalist, who survived the gas tragedy, died on April 11.

In a letter to the state and Indian governments, organisations working for the welfare of gas leak survivors claimed that the group was "five times more vulnerable to Covid-19 than the general population".

The Madhya Pradesh government has now removed the BMHRC from the list of Covid-19 hospitals. But Ms Dhingra said the gas relief ward is yet to open.