Delhi air quality slips, worst since June 12

In a statement released on Sunday, CAQM said it was closely monitoring Delhi’s AQI parameters and it was not enforcing additional Grap measures.

Delhi’s air quality fell to the “poor” category with an Air Quality Index (AQI) reading of 232 on Sunday—a deterioration from Saturday’s reading of 186 (moderate)—as wind speeds calmed in the region and allowed local emissions to gradually accumulate, making it the Capital’s most polluted air day in nearly four months. Delhi last recorded a worse AQI reading on June 12—249.

With forecasts showing Delhi’s air is likely to remain poor for the next few days, the CAQM sub-committee has asked agencies to intensify measures under Stage I. (Sanjeev Verma/HT Photo)

The last time Delhi’s air deteriorated to the “poor” category was October 5, when the AQI reading was 211, resulting in the Commission for Air Quality Management (CAQM) sub-committee enforcing Stage I or the “poor” category measures of on Graded Response Action Plan (Grap) . With forecasts showing Delhi’s air is likely to remain poor for the next few days, the CAQM sub-committee has asked agencies to intensify measures under Stage I.

The Central Pollution Control Board (CPCB) classifies an AQI reading between zero and 50 “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor”, and 401 and 500 “severe”.

In a statement released on Sunday, CAQM said it was closely monitoring Delhi’s AQI parameters and it was not enforcing additional Grap measures, it had directed agencies to be more vigilant, and asked people to follow the “citizen charter”, mentioned in the Grap.

To be sure, the citizen charter is a list of actions suggested by the CAQM for the general public to follow. This includes keeping pollution certificates up to date, ensuring vehicles are not idling at red lights and not disposing of garbage or waste in open spaces.

“On October 5, Delhi’s air quality had deteriorated to the ‘poor’ category. As the air quality has reached the poor category again, actions under Stage I of Grap need to be intensified by all concerned. In view of the AQI of NCR, the commission has reiterated to all implementing agencies of the Central and state governments of NCR to strictly implement actions under Stage I of the Grap and is also urging citizens to cooperate in adherence to the ‘citizen charter’ of the respective stages and assist in effective implementation of Grap measures to improve the overall AQI in the region,” CAQM said Sunday.

According to the revised Grap, which is being implemented for the first time this winter, action is tied to AQI, with the first stage (Stage I or the “poor” category) measures kicking in when the AQI reading crosses 201. The 24 measures under Stage I include steps such as closure of construction and demolition (C&D) activities on plots bigger than 500sqm which have not registered on the web portals of respective NCR state governments; proper implementation of guidelines on dust mitigation measures and sound environmental management of C&D waste; periodic mechanised sweeping and water sprinkling on roads; use of anti-smog guns at C&D sites; prohibition on open burning of biomass and municipal solid waste; strict vigilance and enforcement of PUC norms and stringent prohibitions to not use DG sets as a regular source of power supply.

These measures have remained in place across NCR since October 5. The next Stage – Stage II or “very poor” category measures can be enforced if forecasts show the AQI reading is likely to touch 301 or higher in the next three days.

VK Soni, scientist at IMD and a member of the CAQM sub-committee, said a meeting on Grap will be held if forecasts show the air quality is likely to reach “very poor” category. However, as of now, the current forecasts only warn of “poor” air until October 19. “From October 19 onwards, there may be a change in wind direction to easterlies and this may result in an improvement in air quality,” he said.

According to the Early Warning System (EWS) for Delhi, which the CAQM uses for its forecast, Delhi’s air will be “poor” from October 16 to 19, with predominant surface winds being northwesterly during this period. “The wind speed will be from 4-8km/hr on October 17. It will increase slightly to 4-10km/hr on October 18 and the wind speed will be from 8-12km/hr on October 19,” the EWS forecast on Sunday said.