The Wire Staff 
New Delhi: On Friday (November 15), the air quality in Delhi moved into the “Very Poor” category, a marginal improvement from “Severe” air quality that the national capital witnessed on November 14 and 13. The city’s Air Quality Index (AQI) – which was 424 on the evening of November 14 – was 396 on November 15, based on data released in the Central Pollution Control Board’s (CPCB’s) air quality bulletin on Friday evening.
The government has already implemented Stage III of the Graded Action Response Plan (GRAP), which restricts activities such as specific types of construction, since November 14. Primary schools, meanwhile, also switched to online classes, reported The Indian Express.
On Monday, the Supreme Court will hear a plea on the steps taken to check air pollution in the city. According to IQAIR, which ranks cities across the world based on air quality, New Delhi is currently the second-most polluted city in the world.
Delhi’s AQI wavers between “Severe” and “Very Poor”
AQI is a measure of at least three pollutant levels. One of them is particulate matter (both PM2.5, which is fine particulate matter of diameter less than 2.5 microns, and PM10, which is less than 10 microns in diameter). The AQI ranges from 0 to 500. The higher the AQI, the worse the category gets, as do the impacts of such air on even healthy people. While an AQI between 0 to 50 is considered ideal, an AQI between 401-500 is categorised as “Severe”, and is the worst air quality level per standards followed by the CPCB.
Exposure to such air quality, “affects healthy people and seriously impacts those with existing diseases” as per the CPCB. An AQI between 301 and 400 is categorised as “Very Poor” and prolonged exposure to such air quality can cause respiratory illnesses.
As per the Air Quality and Weather Bulletin for Delhi released on November 15 by the Air Quality Early Warning System for Delhi – a project undertaken by the Indian Institute of Tropical Meteorology Pune – the air quality in Delhi was in the “Severe” category with an AQI of 424 as per the CPCB on November 14 as of 4 p.m.
As per the daily AQI bulletin released by the CPCB on November 15, however, Delhi’s air quality may have improved but only very slightly: it clocked an AQI of 396 as of 4 p.m., taking it out of the “Severe” category and into the “Very Poor” category.
Per the bulletin, PM2.5 was the main pollutant across the city that contributed to the poor air quality. However, this is an average of data from different stations. On November 15, the AQI was based on data from 38 of the 39 weather monitoring stations in the city. Some areas showed higher or lower values. For instance, the AQI as measured by data from the Anand Vihar monitoring station in the city was 445 at 5 pm and PM10 was the main pollutant. The AQI of both Gurugram and Ghaziabad also were in the “Very Poor” category on November 15, at 304 and 341 respectively. However, the PTI reported that AQI in the city was 411, again in the “Severe” category, on November 15.
According to IQAIR, which ranks cities across the world based on air quality, New Delhi is currently the second-most polluted city in the world (as of November 15).
GRAP III enforced; primary schools hold classes online
The Delhi government implemented Stage III of the Graded Response Action Plan (GRAP) on November 14. This means that more restrictions are now in place (such as a strict ban on construction and demolition, except in some cases) to ensure that such activities do not further add to the air pollution levels in the city.
Primary schools in the city will now conduct classes online, Delhi chief minister Atishi Marlena said on Thursday; schools will also remain shut on Saturday. To reduce traffic congestion, which also contributes to local air pollution, she announced staggered working hours for government offices across the city on November 15. On the same day, Delhi environment minister Gopal Rai said that an additional 106 cluster buses would ply in the city while metro trains would make 60 extra trips in view of GRAP-III measures imposed due to worsening air quality. Residents in many parts of Delhi awoke to smog again on Friday, for the third consecutive day, reported Indian Express.
“Coming back to Delhi from Wayanad where the air is beautiful and the AQI is 35, was like entering a gas chamber. The blanket of smog is even more shocking when seen from the air,” tweeted Priyanka Gandhi Vadra, general secretary of the All India Congress Committee, on November 15. “Delhi’s pollution gets worse every year. We really should put our heads together and find a solution for cleaner air. It’s beyond this party or that, it’s practically impossible to breathe especially for kids, elders and those with respiratory issues. We just have to do something about it.”
On Monday, November 18, the Supreme Court will hear a plea seeking enforcement of measures taken to check air pollution in Delhi. This came after senior advocate Aprajita Singh, who has been appointed as amicus curiae in matters related to air pollution, requested for an urgent hearing, the Indian Express reported.