The national Capital breathed better on Wednesday, with the air quality improving significantly after light rains hit the city a day before. The air quality index (AQI) improved to 270, against Tuesday’s 290. Scientists at the Central Pollution Control Board (CPCB) attributed the better air quality to the rain and picking up of wind speed. The day temperature fell to 21.3 degrees Celsius, with cold winds coming from northern India. The AQI units are measured against PM 2.5, the most prominent pollutant in Delhi -NCR (measured in microgram per cubic meters).