Delhi’s air in ‘severe’ category for second day
Delhi’s average AQI stood at 428 at 8am on Thursday. It was 418 (severe) at 4pm on Thursday but touched a peak of 454 at 9pm on Wednesday before gradually improving
Delhi’s air quality remained in the ‘severe’ category on Thursday for the second successive day by breaching the 400-mark on the air quality index (AQI).
The national Capital reported moderate fog with visibility dipping to 300 metres in parts of the city on Thursday morning, keeping Delhi’s air quality index (AQI) in the ‘severe’ range.
Delhi’s average AQI stood at 428 at 8am on Thursday. It was 418 (severe) at 4pm on Thursday but touched a peak of 454 at 9pm on Wednesday before gradually improving.
The Central Pollution Control Board (CPCB) classifies AQI between 0-50 as “good”, between 51 and 100 as “satisfactory”, between 101 and 200 as “moderate”, between 201 and 300 as “poor”, between 301 and 400 as “very poor”, and over 400 as “severe”.
“A layer of fog is spread across the Indo-Gangetic Plains similar to Wednesday but the intensity is less. Delhi’s Indira Gandhi International Airport (Palam) reported its lowest visibility of 300 metres at around 7am on Thursday morning and it remained at 300 metres at 8am too. It was around 700 metres at 5:30am,” said an IMD official.
Also Read:Capital punishment: Delhi air now ‘severe’
No flight diversions or delays were reported from Delhi’s Indira Gandhi International (IGI) airport due to the fog on Thursday morning.
Zero visibility was reported at Palam on Wednesday morning, with over ten flights diverted and over 100 delayed in the season’s first ‘very dense’ fog spell.
The IMD classifies fog as ‘shallow’ when visibility is between 500 metres and 1,000 metres; as ‘moderate’ when between 200 and 500 metres; as ‘dense’ when between 50 and 200 metres and below 50 metres is ‘very dense’ fog.
Delhi also reported its first severe air day of the season on Wednesday, largely due to the thick layer of fog forming across the region. A combination of calm winds and fog meant sunlight could not penetrate till the surface until late Wednesday afternoon — trapping local pollutants close to the surface.
Despite the deterioration to severe, the Commission for Air Quality Management’s (CAQM) sub-committee on the Graded Response Action Plan (GRAP) on Wednesday opted not to invoke stage-3 measures of the emergency-level plan, stating an improvement in AQI is expected by Thursday.
“The Sub-Committee has noted this steep rise in AQI of Delhi owing to this episodic event, since this morning. However, owing to stronger winds, the pollutant concentration and thereby the AQI, is expected to start showing a declining trend Thursday onwards and the AQI is likely to move back to the ‘Very Poor’ category the next day,” said CAQM in a statement on Wednesday evening, adding it will continue to review the situation before taking a decision on stage-3.
Stage-3 measures include a ban on private construction and demolition activities in NCR, a ban on stone crushers and any mining in the NCR; a restriction of plying of BS-3 and BS-4 diesel light motor vehicles (LMVs) in Delhi, Gurugram, Faridabad, Ghaziabad and Gautam Budh Nagar. It also restricts the movement of BS-3 and lower medium goods vehicles (MGVs) and Light Commercial Vehicles (LCVs) from plying in the national Capital.