City witnesses the coldest December 14 in seven yrs
NEW DELHI: Delhi witnessed its coldest December 14 in seven years on Thursday, thanks to strong north-westerly winds.
The maximum temperature was 19.1 degree Celsius, four notches below what is normal this time of the year.
According to the MET department, this was the lowest, the maximum temperature has come down to on December 14, in seven years since 2011. The minimum, however, touched 11.2 degrees, three notches above normal.
“It was a cold day as the maximum temperature dropped substantially. However, technically, we classify a day as ‘cold’ when the maximum temperature drops more than 4.4 degrees Celsius,” Kuldeep Srivastava, a senior MET department scientist said. There was shallow fog in the morning with visibility dropping to 600m.
Usually, because of fog, there is a lot of moisture in the air coupled with calm winds — conditions that increase pollution.
“On Thursday, however, Delhi had a good wind speed of 12km/ hour. This allowed dispersal of pollutants and therefore the air quality did not worsen,” Srivastava said.
Thursday’s average Air Quality Index clocked 265, which is falls under ‘poor’ category. On Wednesday, it was 270 while on Tuesday it was 219. The AQI is calculated on a scale of 0-500.
While PM10 concentration increased from 222.5 micrograms per cubic metre (μg/m3) at 6am to 235μg/m3 at 6pm, the level of PM2.5 saw minimal increase from 135.9μg/m3 at 6am to 138.8μg/m3 at 6pm. On Friday, mainly clear sky is expected with shallow fog in the morning. The maximumandminimumtemperature expected around 19 and 9 degrees Celsius respectively.