NEW DELHI — Dense 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. Delhi’s air pollution levels have remained at what the federal government calls a “severe” level for the last two days, which the government says can cause respiratory effects to healthy people and seriously affect the health of people with heart or lung disease. On Sunday, official index readings were over 450 at several monitoring stations, up from 4