Pollution levels in Kolkata nearly matched that of Delhi today, with its air quality index (AQI) slipping into the "very poor" category. Official sources said the city's PM2.5 count stood at 356 around eight on the morning after Diwali, just 10 points shy of Delhi's 365. PM2.5 refers to atmospheric particulate matter with a diameter of less than 2.5 micrometres. Exposure to these particles can cause premature death from heart and lung diseases, besides chronic disorders such as asthma, bronchitis and other respiratory problems.
