Delhi's air quality significantly improved Thursday after rainfall managed to wash away pollutants but authorities warned that the respite would not last long due to unfavourable weather. The city's air quality index or AQI dropped to 208 from over 400 in the last three days, according Central Pollution Control Board (CPCB) data. The respite comes after Delhi's air quality battled severe pollution for three consecutive days from Monday but last night's rainfall with moderate winds managed to wash away the pollutants significantly, the Centre-run System of Air Quality and Weather Forecasting (SAFAR) said. An AQI between 201 and 300 is considered 'poor', 301 and 400 'very poor' and 401 and 500 'severe'. Neighbouring Ghaziabad and Faridabad recorded 'poor' air quality, while Gurgaon and Noida recorded 'moderate' air quality, CPCB data showed. Seventeen areas in Delhi recorded 'poor' air quality and in 19 areas it was at 'moderate'. The overall PM2.5 level - fine particulate matter in the air with a diameter of less than 2.5 micrometre - was recorded at 95 and the PM10 level at 164, it said The AQI on Monday was recorded at 412, 415 on Tuesday and 413 on Wednesday morning. The SAFAR said the air quality would further improve during the day as moderate wind speed is positively working to disperse pollutants which is the key factor now to keep pollution in check. "However, respite is expected not to last longer as humidity is very high and temperature is likely to cool. Both factors are unfavourable and push AQI to 'very poor' level by tomorrow (Friday)," the SAFAR said.