GURUGRAM: The Commission for Air Quality Management (CAQM), on Wednesday, imposed Stage-III restrictions of the Graded Response Action Plan (GRAP) in Delhi-NCR after pollution levels rose to the ‘very poor’ category.
Gurgaon‘s air quality index (AQI), recorded at 312 (very poor) on Wednesday, deteriorated sharply from the previous day’s ‘poor’ reading of 238. Experts attributed this to poor dispersion of pollutants due to lower wind speeds. The last time Gurgaon grappled with ‘very poor’ air was over a month back on Dec 27 with an AQI of 349.
Similarly, Delhi’s AQI worsened to 365 (very poor) from 276 (poor) on Tuesday.
The GRAP sub-committee of CAQM convened an emergency meeting and invoked GRAP-III, noting the spike in AQI due to variable wind directions, smog, and low ventilation for pollutants. This is in addition to the measures enforced already under stages I and II of GRAP.
Stage-III measures include a comprehensive nine-point action plan to curb pollution. These steps include strict restrictions on earthwork, piling, demolition, and other dust-generating activities across the NCR. Only essential projects such as railways, metro services, airports, national security, hospitals, and sanitation projects can continue, subject to strict compliance with dust control norms.
The use of BS-III petrol and BS-IV diesel cars is restricted under this stage.
The CAQM order mandated hybrid classes — both physical and online mode (wherever feasible) — for children up to class 5 in Delhi, Gurgaon, Faridabad, Ghaziabad, and Gautam Budh Nagar.
Of the four monitoring stations in Gurgaon, Sector-51 was the worst hit at 330, followed by Teri Gram which was just a few points away from the ‘very poor’ category at 295. Gwalpahari and Vikas Sadan stations did not record AQI readings due to insufficient data.
The wind speeds dropped to 5kmph on Wednesday from the previous day’s 12kmph, hampering the dispersion of pollutants, experts said.
The System of Air Quality and Weather Forecasting and Research (Safar) predicted further deterioration of air quality over the next three days with wind speeds likely to go below 5kmph. “Smog or mist fog is likely in the evening and night with mainly clear sky on Jan 31,” Safar stated.
A ventilation index lower than 6000 m2/s and an average wind speed less than 10kmph is unfavourable for dispersion of pollutants.
The level of PM2.5 — a toxic particulate matter that reaches the blood via the lungs — was the worst at Sector-51 (354 µg/m³), followed by Gwalpahari (312 µg/m³), Teri Gram (267 µg/m³), and Vikas Sadan (234 µg/m³).
Teri Gram recorded the highest levels of PM10 in the city at 330 µg/m³. It was followed by Sector 51 (321 µg/m³) and Gwalpahari (243 µg/m³). This data was not recorded at Vikas Sadan.
Central Pollution Control Board’s (CPCB) annual permissible limits are 60µg/m³ for PM2.5 and 100 µg/m³ for PM10.
“While the concentration of pollutants varies according to seasons, the sources of emissions remain constant throughout the year. When meteorological conditions fail to disperse pollutants, the air deteriorates,” said Shubhansh Tiwari, a research associate at the Centre for Science and Environment (CSE).
HSPCB officials said local emissions are responsible for higher AQI for most part of the year. They cited factors like suspension of road dust due to vehicular traffic, increase in construction activities, and waste burning as particular concerns that have increased pollutants.
“We have been notifying civic bodies to carry out measures to mitigate pollutants,” said Vijay Chowdhury, regional officer, Gurgaon.
Guidelines issued by the Central Pollution Control Board state that when AQI is ‘poor’, breathing discomfort can be felt by most people on prolonged exposure. An AQI between zero and 50 is considered ‘good’, 51 and 100 ‘satisfactory’, 101 and 200 ‘moderate’, 201 and 300 ‘poor’, 301 and 400 ‘very poor’, and 401 and 500 ‘severe’.
