ense toxic smog blanketed India’s capital on Monday, pushing air pollution levels to their worst levels in weeks, disrupting travel and causing authorities to impose the strictest containment measures.

More than 40 flights were cancelled and several dozens delayed. Over 50 trains arriving and departing from New Delhi were delayed by several hours, authorities said.

Healthcare experts warned residents to avoid all outdoor activities as hospitals reported an influx of patients with breathing difficulties and eye irritation.

“New Delhi is a gas chamber right now. Air purifiers can help only a bit, so it’s high time the government comes up with some permanent solutions” said Naresh Dang, a physician at Max Healthcare.