NEW DELHI — The toxic haze blanketing New Delhi was so severe on Tuesday that politicians announced plans to close schools, flights were delayed and the chief minister of Delhi state said the city had “become a gas chamber.”

For Arvind Kumar, a chest surgeon for more than three decades, the situation is adding to a growing health crisis in the region. “I don’t see pink lungs even among healthy nonsmoking young people,” he said in a telephone interview on Tuesday. “The air quality has become so bad that even if you are a nonsmoker you are still suffering.”

The thick, acrid fog is not new to Delhi, where it settles around this time every year, covering the capital in vehicle emissions and smoke from the burning of crops in neighboring states and from fireworks from Diwali, the Hindu festival of lights. But in recent years, the problem appears to have worsened.