Senior Congress leader Ajay Maken on Monday questioned the availability of air pollution data from Delhi's monitoring network on Diwali night, alleging that PM2.5 readings from 25 of the city's 39 monitoring stations were missing during a period when pollution levels at the remaining stations were nearly 38 times the World Health Organisation's (WHO) 24-hour guideline limit.
Citing Central Pollution Control Board (CPCB) data, Maken said no readings were recorded at the 25 stations between 2 am and 3 am on November 9. The average PM2.5 concentration at the nine stations with available data during that hour was 576 micrograms per cubic metre (µg/m³), he said in a post on X.
The concentration was 38.4 times the WHO's 24-hour limit of 15 µg/m³ and 2.5 per cent higher than the 562 µg/m³ recorded at the same nine stations during the corresponding period on the previous Diwali.
Maken listed the stations where data was unavailable, including Anand Vihar, Ashok Vihar, Aya Nagar, Bawana, Chandni Chowk, Dwarka Sector 8, ITO, Mundka, Najafgarh, Narela, Punjabi Bagh, R K Puram and Wazirpur.
He also shared hourly PM2.5 readings from the two Diwali nights, which showed higher pollution levels this year through much of the evening. The average concentration at 6 pm was 141 µg/m³, against 107 µg/m³ on the previous Diwali, an increase of 31.5 per cent. At 7 pm, it rose to 181 µg/m³ from 146 µg/m³.
The gap narrowed as pollution levels climbed. At 8 pm, the average stood at 265 µg/m³, compared with 222 µg/m³ a year earlier, while the 9 pm reading was 403 µg/m³ against 354 µg/m³.
PM2.5 levels crossed 500 µg/m³ by 10 pm, reaching 506 µg/m³, and rose to 515 µg/m³ an hour later. The concentration peaked at 610 µg/m³ at midnight, equivalent to 40.6 times the WHO limit, before declining to 597 µg/m³ at 1 am and 576 µg/m³ at 2 am, according to the figures shared by Maken.
"Air pollution levels are 38.4 times the WHO limit—and this is despite data from 25 monitoring stations not being recorded," he said.
Delhi's air quality also remained severely affected on Monday morning, with thick smog enveloping several parts of the city and reducing visibility, ANI reported. The deterioration came a day after Diwali celebrations.
Visuals from Inderlok showed a dense layer of smog over the area in the early hours, while other parts of the capital also woke up to hazy conditions.
According to CPCB readings cited by ANI, the AQI near Ghazipur stood at 418, falling in the severe category, while the reading near Akshardham was 337, categorised as very poor.
(With inputs from ANI)
