NEW DELHI: Delhi received highest rainfall recorded for the month of December since 1991. From December 12 evening till December 13, the rainfall received in these days was 33.5 mm, highest for a December day in 28 years. Due to the record rainfall, the temperature in the NCT dropped five degrees Celsius. Also, the air quality has improved significantly due to the increased wind speeds, which remained between 25 kmph and 30 kmph. The Central Pollution Control Board (CPCB) data showed an improvement in AQI from 429 to 240. Kuldeep Srivastava, head of the IMD’s regional weather forecasting centre, attributed this unprecedented rainfall to rainfall, hailstorm and snowfall in the western Himalayan region.