Delhi air quality improves after rainfall, but AQI still in 'poor' category

Delhi experienced a marked improvement in air quality on Friday (January 17) morning, with the Air Quality Index (AQI) recorded at 294, according to the Central Pollution Control Board (CPCB). This figure, though classified as “poor,” reflects a notable recovery from Thursday’s AQI of 350. Earlier in the week, the AQI stood at 344 on Wednesday and 250 on Tuesday, the latter also categorised as “poor.”

 

The improvement in air quality coincided with the revocation of Stage 4 of the Graded Response Action Plan (Grap) on Thursday. A spell of light rainfall, brought on by a western disturbance, and strong surface winds from late Wednesday to Thursday morning significantly helped disperse pollutants.  

 

Delhi's AQI dropped from 386 at 4 pm on Wednesday to 302 at the same time on Thursday, remaining in the “very poor” category. By 8 pm on Thursday, it further improved to 288, falling into the “poor” range.   

 

Rainfall data from the Safdarjung weather station, representative of Delhi’s weather, showed 3.9 mm of rainfall in the 24 hours leading up to 8.30 am on Thursday. Palam recorded the highest rainfall at 10.1 mm, followed by 9.7 mm at the Ridge station.  

 

The India Meteorological Department (IMD) has forecast another western disturbance from January 18, potentially bringing light rainfall to northwest India on January 21. Meanwhile, an orange alert has been issued for dense to very dense fog on Friday and Saturday.

 

Delhi weather round-up

 

Delhi's weather saw a rise in minimum temperature due to the rainfall and overcast skies, climbing from 6 degrees Celsius to 10.3 degrees Celsius on Thursday —three degrees above normal. The maximum temperature also rose from 18.1 degrees Celsius to 19.6 degrees Celsius.  

 

“Fresh snowfall in the hills has been recorded, which will lead to a drop in minimum temperatures to around 6 degrees Celsius by January 19. Another western disturbance, however, is expected to cause a rise in temperatures thereafter, with the maximum hovering between 19 and 21 degrees Celsius,” an IMD official said.  

 

Delhi has recorded 6.1 mm of rainfall this month against the long-period average of 19.1 mm for January.  

 

Classes to continue in hybrid mode  

 

Due to earlier implementation of Stage 4 of Grap, the Directorate of Education, Delhi, had directed schools to conduct classes for students up to Class IX and XI in hybrid mode. This decision applied to government, government-aided, unaided private schools, and those under NDMC, MCD, and the Delhi Cantonment Board.