Expect a further dip in temperature today as cold wave hits DelhiUpdated: Dec 14, 2017 07:47 IST
The temperature in the national Capital is expected to dip further from Thursday due to northerly winds, the MeT department has said.
Officials said Thursday will experience mainly clear skies with the possibility of shallow fog in the morning. The maximum and minimum temperatures would be around 21 and 9 degree Celsius respectively.
“On Thursday, we are expecting visibility to be around 500m due to fog. The temperature is also expected to dip to 8-9 degrees. This is because of northerly wind, which will decrease the temperature as snow fall has already happened. The winds blowing in Delhi are northwesterly,” said Kuldeep Srivastava, a senior MeT department scientist.
On Wednesday, the maximum temperature was recorded at 21.3 degrees Celsius, two degrees below what is normal this time of the year. The minimum temperature, however, touched 12 degrees Celsius, three notches above normal.
“There was moderate fog in the morning with visibility dropping to 300m. In the rest of northwest India, however, there was dense fog. Usually because of fog there is a lot of moisture in the air and coupled with calm winds, these conditions increase pollution. However, from Tuesday, Delhi has experienced a good wind speed of 10km/hour. Even though the air quality has worsened, it is still not that bad,” Srivastava said.
Wednesday’s average Air Quality Index was 270, which falls under ‘poor’ category. On Tuesday, it was 219. This is a marked improvement from 361 on Monday and 377 on Sunday, thanks to the rain on Monday night. The AQI is calculated on a scale of 0-500. An AQI between 0-50 is considered good, 51-100 satisfactory, 101-200 moderate, 201-300 poor, 301-400 very poor and 401-500 severe.
The levels of PM10 and PM2.5 saw marginal increase throughout the day. While PM10 concentration increased from 188.1μg/m3 at 6am to 202.7μg/m3 around 7pm, the level of PM2.5 saw minimal increase from 126.4μg/m3 at 6am to 129.7μg/m3 at 6pm
Both PM10 and PM2.5 are ultra fine particles that are the dominant pollutants in Delhi.
On Thursday, because of the fog, pollution levels might increase. But if the winds continue to be favourable, the air quality won’t deteriorate much. From Friday, however, as the cold and dry north westerly winds pick up speed, the pollution levels are expected to go down again.
First Published: Dec 14, 2017 07:37 IST