Delhi Air quality severe as an AQI between 0-50 is considered 'good', 51-100 'satisfactory', 101-200 'moderate', 201-300 'poor', 301-400 'very poor' and 401-500 'severe'. Above 500 falls in the 'severe plus' category. German Chancellor Angela Merkel, who is on a visit to India, expressed concern over the air quality in Delhi.