Delhi on Wednesday woke up to a haze that the city is used to during winters. With visibility down and a thick smog-like cover of dust enveloping the air, conditions are not what Delhi witnesses at this time of the year. Delhi's air quality deteriorated severely on Wednesday mainly due to dust storms from Rajasthan, a senior official at the pollution control board said. The dusty conditions are likely to prevail over the next three days. According to the Central Pollution Control Board (CPCB), the air quality index, which measures the concentration of harmful particulate matter in the air, hit a level of 445, on a scale where anything above 100 is considered unhealthy. The CPCB data further cites the reason for hazy conditions and limited visibility being the PM10 (particles with diameter less than 10mm) level which was 778 in Delhi-NCR and 824 in Delhi, respectively. According to a statement issued by Environment Ministry, "The high pollution levels during this time of the year in Delhi are unusual and primarily due to dust storms from Rajasthan. Rajasthan is facing extremely dry weather conditions, with high temperatures and wind speeds." It said the wind direction in Delhi since June 10 has changed to West and North West and then since June 12 to West and South West, due to which hot air, along with dust from Rajasthan has started moving into Delhi. Major construction agencies, municipal corporations and Delhi Pollution Control Committee (DPCC) have been alerted to ensure adequate water sprinkling to keep the dust down and be prepared for any further measures. According to the India Meteorological Department (IMD), the current surface winds in Delhi are in the range of 5-6 m\/sec and wind direction is West to South West, which is likely to continue over the next three days. According to A Sudhakar, member secretary of CPCB, the board will be holding a meeting with all the agencies if this pollution level continues. Emergency actions will be required to be taken like stopping construction work along with stopping the use of hoy-mix plants and stone crushers, he added.