Despite being the festival week Delhi residents it began it by coughing, rubbing their eyes and gasping for clean air. The AQI (Air Qality Index) on Monday dropped to the season's low of 426. The concentration of particulate matter 2.5 stayed in the severe zone for at least four hours between 11 AM and 3 PM. The dip in air quality as experts say is because of moisture in the North-Westerly wind coupled with low surface wind speeds. Application that monitor wind speeds and satellite images showed plumes of smoke being brought in from Punjab. Speaking exclusively to NDTV, CPCB Chairman SPS Parihar says, "In Delhi, the average wind speed in winter ranges between one and three metres per second. 24% of pollution levels are due to biomass burning and at least 40% comes from vehicular emissions but the government alone cannot combat pollution. Local emissions can be controlled by RWAs and residents."