Delhi’s AQI stays ‘poor’ as city braces for worsening air quality around Diwali

The city recorded its first ‘poor’ air quality day of the season on Tuesday, also the first in Delhi since the pre-monsoon period.

Delhi’s air quality remained in the ‘poor’ category for a second straight day on Wednesday, deteriorating marginally in the last 24 hours, even as the Supreme Court allowed bursting of ‘green firecrackers’ for Diwali from October 18-21.

A thin layer of smog engulfs Kartavya Path in New Delhi. (ANI)

The average air quality index (AQI) stood at 213 (poor) at 11am, a marginal rise from Tuesday’s 4pm reading of 211 (poor), Central Pollution Control Board (CPCB) data showed.

The city recorded its first ‘poor’ air quality day of the season on Tuesday, also the first in Delhi since the pre-monsoon period, when Delhi recorded a poor air day on June 11 (245). The spike in AQI — over 200 — also prompted the Commission for Air Quality Management (CAQM) in NCR and adjoining areas to hold an emergency meeting and invoke stage-1 measures of the Graded Response Action Plan (GRAP) across NCR with immediate effect. The plan, meant to be enforced annually, usually sees multiple stages get triggered in the winter months, as Delhi’s air quality nosedives.

Stage-1 largely has ‘preventive’ rather than ‘restrictive’ measures and lists 27 directions, including periodic mechanised sweeping and water sprinkling on roads, strict vigilance of PUC norms and action against visibility polluting vehicles, regular lifting of solid waste and stopping construction and demolition (C&D) sites in Delhi with an area of more than 500 sqm which are not registered with the state government through their online portal on dust.

“Delhi’s AQI on October 14 was recorded at 211 (poor). Further, the forecast by the IMD and IITM has also predicted AQI to remain in the ‘poor’ category in coming days. The CAQM sub-committee, accordingly, decides to invoke all actions under Stage-I (‘poor’) of the extant GRAP in the entire NCR, with immediate effect,” the CAQM had said in a statement on Tuesday.

CAQM also urged people in NCR to follow the ‘citizen charter’ of Stage-1 of GRAP, which asks people to celebrate festivals in an eco-friendly manner and avoid firecrackers; keep PUC certificates up to date; keep vehicle engines properly tuned; to turn off engines at red lights and to not litter or dispose waste in open spaces among others.

Forecasts by the Centre’s Air Quality Early Warning System (EWS) for Delhi shows no relief is likely ahead, with ‘very poor’ AQI likely around or after Diwali.

“Delhi’s air quality is very likely to be in the ‘poor’ category from October 15 till October 17. The outlook for the subsequent six days shows the air quality is likely to be between the ‘poor’ to ‘very poor’ category,” the EWS said in its daily bulletin.

The CPCB classifies air quality on a scale where 0-50 is ‘good’, 51-100 ‘satisfactory’, 101-200 ‘moderate’, 201-300 ‘poor’, 301-400 ‘very poor’, and 401-500 ‘severe’.

The Decision Support System (DSS) – a model which calculates the estimated contribution of sources of pollution to Delhi’s PM 2.5, had said the contribution of stubble burning was only around 0.53% on Tuesday, marginally down from a contribution of 0.62% on Sunday. The top contribution to Delhi’s PM 2.5 on Tuesday was 19.8% from Delhi’s transport sector, followed by Gurugram (9.3%) and Delhi’s residential sector (5.1%), data showed.

Meteorological conditions are also likely to be unfavourable in the coming days. The India Meteorological Department has said mist is likely to form in the city in the early hours of the day from Wednesday, with shallow fog possible in the morning October 19 onwards.

Mahesh Palawat, vice president at Skymet, said strong winds are unlikely at the moment, with no significant change in the weather likely. “No rain or strong winds are expected, to settle pollutants or blow them away,” he said.