Delhi’s air quality has deteriorated sharply, plunging into the hazardous zone amid dense smog and fog. Authorities have invoked Stage-IV emergency measures to combat the severe pollution affecting the capital and NCR region.
Air pollution in Delhi and regions around the national capital, which had already slipped into the ‘severe’ category on Saturday, worsened further on Sunday as a thick layer of toxic smog blanketed the city and other areas, pushing air quality to hazardous levels and severely impairing visibility in several areas.
Data from the Central Pollution Control Board (CPCB) showed Delhi’s average air quality index (AQI) rising to 461 at 7 am, up from 431 a day earlier.
ALL MONITORING STATIONS IN SEVERE ZONE
All 40 air quality monitoring stations across the city recorded readings in the ‘severe’ category, with multiple locations nearing the maximum measurable limit. Rohini recorded an AQI of 499, followed closely by Bawana at 498, Vivek Vihar at 495, Ashok Vihar and Wazirpur at 493 each, Narela at 492 and Anand Vihar at 491.
Other parts of the capital also remained heavily polluted, including ITO (485), Mundaka (486), Punjabi Bagh (478), Nehru Nagar (476), Chandni Chowk and Okhla (470 each).
Even relatively greener pockets such as Lodhi Road (400) and Najafgarh (404) failed to escape the grip of toxic air.
NCR ALSO SUFFERS
The air quality crisis extended well beyond the national capital, with several cities across the National Capital Region (NCR) also recording alarming pollution levels.
Noida registered an AQI of 470, placing it firmly in the ‘severe’ category, while Ghaziabad recorded a similarly hazardous 460. Gurugram’s air quality remained ‘very poor’ at 348, while Faridabad saw relatively lower but still concerning levels, with an AQI of 220, classified as ‘poor’.
DENSE FOG CUTS VISIBILITY
The worsening pollution was visible from the early hours, as dense smog mixed with fog engulfed large parts of Delhi, reducing visibility sharply.
In some areas, visibility dropped to near zero, disrupting early-morning movement and prompting authorities to activate low-visibility procedures at the Indira Gandhi International Airport. While flight operations continued, officials said pilots were operating under precautionary protocols due to fluctuating visibility conditions.
IMD ISSUES DENSE FOG WARNING FOR DELHI
According to the India Meteorological Department (IMD), visibility at the IGI Airport was expected to reduce to as low as 100 metres in dense fog during the early morning hours on Sunday, before improving to around 800 metres in shallow fog later in the day.
The IMD forecast had warned of moderate to dense fog at many places across Delhi during the morning hours of December 14, with shallow to moderate fog likely to persist in the following days as well.
WEAK WINDS WORSEN CONDITIONS
In its daily weather bulletin issued on Saturday, the IMD said a western disturbance persisting over north Pakistan and the presence of a strong subtropical westerly jet stream over northwest India were influencing weather conditions over the region.
The department forecast partly cloudy skies over Delhi for the next 48 hours, followed by clearer conditions, but cautioned that mist, haze and fog would continue during night and morning hours.
Dense fog was expected at isolated places on Sunday morning, with shallow to moderate fog likely on December 15 and shallow fog thereafter.
GRAP STAGE-IV INVOKED ACROSS NCR
On Saturday night, amid the rising pollution trend, the Sub-Committee of the Graded Response Action Plan of the Commission for Air Quality Management in NCR and Adjoining Areas (CAQM) held an emergency meeting and decided to invoke all actions under Stage-IV of the extant GRAP, classified as ‘Severe+’ air quality, with immediate effect across the entire NCR.
The decision was taken after Delhi’s AQI rose steadily from 431 at 4 pm to 436 at 5 pm and further to 441 at 6 pm.
METEOROLOGICAL FACTORS BEHIND SUDDEN AQI SPIKE
CAQM said the sudden deterioration in air quality was largely driven by unfavourable meteorological conditions rather than a spike in emissions.
A feeble western disturbance approaching northwest India led to a sharp reduction in wind speed, at times turning calm, a shift in wind direction from westerly to easterly, and increased moisture in the lower atmosphere.
These winter conditions are conducive to the formation of smog and fog, trapping pollutants close to the surface and preventing their dispersion.
5-POINT EMERGENCY ACTION PLAN ROLLED OUT
Under Stage-IV of GRAP, a five-point emergency action plan has been enforced with immediate effect across Delhi-NCR.
The measures include stopping the entry of BS-IV diesel trucks into Delhi, except those carrying essential commodities or providing essential services, while allowing LNG, CNG, electric and BS-VI diesel trucks.
A strict ban has been imposed on the plying of Delhi-registered diesel-operated BS-IV and below heavy goods vehicles, except for essential services.
CONSTRUCTION, MINING AND STONE CRUSHERS SHUT
All construction and demolition activities have been completely banned, including linear public infrastructure projects such as highways, roads, flyovers, power transmission lines and pipelines.
Stone crushers, mining operations and associated activities across the NCR have also been ordered to shut down.
SCHOOLS SHIFT TO HYBRID MODE
In the education sector, state governments in the NCR and the Delhi government have been directed to conduct classes for students from Class VI to IX and Class XI in a hybrid mode, combining physical and online learning where feasible.
Authorities may also consider extending hybrid classes to other areas of the NCR. The option to attend online classes will rest with students and their guardians.
Additional emergency measures, including the closure of colleges and non-essential commercial activities and the implementation of odd-even vehicle norms, may also be considered by state governments.
HEALTH ADVISORY ISSUED
CAQM has appealed to residents of the NCR to strictly follow the Citizen Charter under GRAP.
Children, the elderly and people suffering from respiratory, cardiovascular or other chronic illnesses have been advised to avoid outdoor activities and remain indoors as much as possible, using masks if stepping out is unavoidable.
BRIEF RELIEF EARLIER IN WEEK PROVES SHORT-LIVED
Delhi’s air quality had briefly improved earlier in the week, dipping to 282 on Tuesday and 259 on Wednesday, but the relief proved short-lived.
Pollution levels climbed again from Thursday onwards, crossed into the ‘severe’ category on Saturday and worsened further on Sunday as dense fog and toxic smog continued to choke the city, raising concerns that hazardous conditions may persist in the coming days.
WHAT AQI LEVELS MEAN FOR HEALTH
As per CPCB norms, the AQI is calculated based on eight pollutants — PM2.5, PM10, nitrogen oxides, sulphur dioxide, ozone, carbon monoxide, ammonia and lead.
AQI values between 301 and 400 fall under the ‘very poor’ category, while readings above 401 are classified as ‘severe’, posing health risks even to healthy individuals.
