Former West Bengal Chief Minister Buddhadeb Bhattacharya remains 'critical but stable', as per his health bulletin released by the hospital in which he is undergoing treatment on Sunday.

The hospital said he is on 'mechanical ventilation'.

"Relevant conservative medical management is being continued," the statement said.

Buddhadeb Bhattacharya has been suffering from respiratory problems for a prolonged period.

According to family sources, he started feeling unwell after lunch on Saturday, July 29, and was subsequently admitted to Woodlands Hospital.

He was suffering from a fever for the past four days.

The oxygen saturation level in his body was gradually decreasing, reaching 68%. The level of carbon dioxide was also increasing.

As he slipped into a state of drowsiness, his personal physicians initially attempted to stabilize his condition using high-flow nasal oxygenation. Although his oxygen saturation level increased to 80%, his doctors decided to rush him to hospital for critical care.

He was brought to the Woodlands Hospital via Green Corridor accompanied by his wife, Meera Bhattacharya.

Hospital sources said that Bhattacharya has been affected by bilateral pneumonia. He has been suffering from chronic obstructive pulmonary disease (COPD) for a prolonged period which was worsened further by COVID-19 infection, severely affecting his respiratory apparatus.

Chief Minister Mamata Banerjee and Governor C V Ananda Bose visited Bhattacharya in the hospital.

Bhattacharya, a senior Communist leader, remained the Chief Minister between 2001-2011.