The AQI takes into account five chief pollutants, including the PM10 and PM2.5.
Advising parents to send their children for classes wearing masks and shifting outdoor activities indoors are among the steps taken by schools in Delhi-NCR to deal with pollution as the air quality continues to be in a severe category.
While schools reopened on Wednesday after the Diwali break, a Gurgaon school principal said they had sent an advisory to parents on Monday to not send their children for classes without masks.
"When I woke up on Monday morning, I just knew that this is not going to be normal soon. We sent advisories to parents to mandatorily send their wards with masks," said Nidhi Kapoor, Principal, Euro International School in Gurgaon.
According to a representative at St Mark's Senior Secondary School, Janakpuri, "We have shifted the venue of morning assembly indoors and advised parents to send their wards wearing masks so whenever they are outdoors they have limited exposure to toxic air."
"Children with special needs and students with medical or respiratory issues are allowed to be on excused leave. Sports, PE and team practices are being conducted considering the potential hazards of outdoor activities and the surrounding environment. Appropriate precautions are taken as per the established safety protocol. Parents are periodically being informed about the cancelation of team practices in the morning or the afternoon sports," said Neena Kaul, Principal, Heritage Xperiential Learning School.
Following a spike in the pollution level, Chief Minister Arvind Kejriwal announced on Wednesday that the Delhi government will start distributing masks among school students from Friday.
"Fifty lakh N95 masks would be given to students in both government and private schools in Delhi. A kit of a mask having two pieces of N95, one of the good quality masks for tackling smog, will be given to students. Masks will be distributed for one week," he said.
The skies over the national capital were a smoky grey on Wednesday as the sun struggled to shine through the haze with the air quality continuing to be in the "severe" category in the city and the adjoining areas.
An Air Quality Index (AQI) between 401-500 falls in the "severe" category and anything beyond that is "severe-plus emergency".
The AQI takes into account five chief pollutants, including the PM10 and PM2.5. The higher the AQI value, the greater the health concern.
According to the Central Pollution Control Board, the air quantity index was 416 at 11 am on Wednesday.