The air quality in the National Capital Region, including Delhi, again went down to "very poor" by Wednesday morning from "poor" for a day only in the wake of moderate rain on Monday. According to the Central Pollution Control Board (CPCB), the air quality at 11 of the 21 monitoring stations across NCR was "very poor", as against only four regions on Tuesday night. In Delhi, concentration of major pollutant PM2.5 - air particles with diameter less than 2.5 micrometers - was 133 units at 15 active monitoring stations, and 131 units at 21 stations across NCR, considered "very poor". On Wednesday, the number of areas exposed to toxic air jumped from four (Tuesday night) to 11 towards noon. The most-polluted areas included Anand Vihar in east Delhi, Delhi Technical University in north Delhi, ITO, Mandir Marg and Lodhi road in central Delhi, Siri Fort and R.K Puram in south Delhi, Sector 125 in Noida and Vasundhara in Ghaziabad. The PM2.5 in these areas ranged between 123 and 194 units - five to eight times the permissible limit. According to System of Air Quality and Weather Forecasting And Research (SAFAR) the overall Air Quality Index (AQI) across 10 stations in the NCR was 252 at noon, as compared with 219 at 4 p.m. on Tuesday after 7.8 mm rainfall. As per the India Meteorological Department (IMD), the NCR with high moisture has no chances of rains on Wednesday and Thursday. "Currently, Delhi is experiencing north-westerly winds with low speeds of 5 to 10 kmph," an IMD official told IANS.