Delhi chokes before Diwali: world's most polluted major city as GRAP-III curbs kick in

Air quality in India's capital Delhi worsened again on the eve of Diwali. On Saturday morning, November 7, the city's air quality index (AQI) stood at around 364, in the "very poor" category, while Swiss air-quality monitor IQAir's live ranking listed Delhi as the world's most polluted major city. The Commission for Air Quality Management (CAQM) invoked Stage III of the Graded Response Action Plan (GRAP) on Friday evening, and students up to Class 5 across Delhi and surrounding areas have switched to hybrid learning.

Several monitoring stations in the "severe" range

According to Central Pollution Control Board (CPCB) data, Delhi's AQI was around 364 on Saturday morning, a modest improvement on Friday's 24-hour average of 382 at 4 p.m., but still far above healthy levels. Of 59 operational monitoring stations, 18 recorded air quality in the severe category, with fine particulate matter PM2.5 the dominant pollutant at most stations. Individual locations were higher still: Punjabi Bagh recorded 453, Jahangirpuri 447 and Rohini 444. Reuters reported that IQAir, using the US air quality index, put Delhi at 581 at 10:35 a.m. — double that of Lahore in neighbouring Pakistan, at 285. Local media, citing official data, said Friday was Delhi's worst pre-Diwali air in eight years.

Stage III curbs: construction halt, vehicle limits, hybrid schooling

The CAQM invoked GRAP Stage III measures across Delhi-NCR on Friday evening. The measures include a ban on dust-generating construction and demolition work, asking governments and private offices to consider allowing 50 percent of staff to work from home, and restrictions on vehicles. Delhi Environment Minister Manjinder Singh Sirsa said in a video message that schools up to Class 5 in Delhi, Noida, Ghaziabad, Gurugram, Faridabad and Sonipat must shift to hybrid mode.

Forecast: severe air at least through November 9

The forecast from the Indian Institute of Tropical Meteorology indicates Delhi's air could remain in the severe category from November 7 to 9, followed by conditions ranging between severe and very poor for another six days. The ventilation index is forecast at 3,000 square metres per second on November 8 and 4,000 on November 9 — below the 6,000 threshold, combined with average wind speeds below 10 kilometres per hour, considered unfavourable for dispersing pollutants. Diwali falls on Sunday, November 8, and the authorities fear firecrackers will push pollution higher still. The opposition Aam Aadmi Party has alleged that the Delhi government is manipulating AQI data.

(Sources: Reuters, CPCB, ANI, The Daily Jagran.)