Many of India's big cities are experiencing such hazardous air pollution that it almost defies belief. The standard measurement for healthy, normal, breathable air is set at a level of 50 according to the Air Quality Index (AQI). A level of 300 means the air is hazardous to breathe. The AQI website says 300 represents a health alert and the city should be put under emergency conditions. The website says that, "everyone may experience more serious health effects". On November 8, the city of Chandrapur in Maharashtra reached an AQI level of 824, to become India's most polluted city. The capital New Delhi has reached an AQI of 724. Environmentalists say many cities are now like "gas chambers".