The Commission for Air Quality Management (CAQM) took decisive action on Saturday by imposing Stage-IV restrictions under the Graded Response Action Plan (GRAP). This move came as toxic smog thickened over Delhi, pushing pollution levels deeper into the severe category. The enforcement followed just a day after Stage-III measures were activated.
What Stage-IV Restrictions Entail
Under the new curbs, all non-Delhi registered vehicles that do not meet BS-VI emission norms are now banned from entering the city. The restrictions also include a complete prohibition on construction and demolition activities across the National Capital Region (NCR). Additionally, non-essential BS-IV or lower diesel goods carriers cannot enter Delhi. Schools have been instructed to switch to hybrid learning modes to reduce exposure.
Sharp Rise in Air Quality Index
Delhi's Air Quality Index (AQI) showed a worrying spike on Saturday. At 4 pm, the AQI stood at 400, but it rose sharply to 428 by 8 pm. This increase was attributed to factors like western disturbance, calm winds, and poor dispersion of pollutants. The AQI scale ranges from 0 to 500, with readings above 400 classified as severe. For context, Friday's AQI was 354, indicating a rapid deterioration.
The CAQM sub-committee explained its decision. "To prevent further deterioration, we unanimously decided to invoke all actions under Stage-IV of GRAP," the panel stated. Stage-IV is triggered when air quality reaches the 'Severe+' level, with an AQI over 450. The measures took effect immediately across the NCR.
Historical Context and Local Hotspots
This is not the first time Stage-IV has been imposed. The last instance occurred between December 13 and 24. Prior to that, Delhi's AQI touched 401 on December 29. Several areas in the city recorded even higher pollution levels on Saturday. Anand Vihar reported an AQI of 483, while Dwarka Sector-8 reached 460. Other hotspots included Wazirpur (459), Vivek Vihar (458), Mundka (456), Nehru Nagar (453), Punjabi Bagh (452), Rohini (450), Chandni Chowk (449), and Siri Fort (445).
Compliance Issues and Contributing Factors
The CAQM had already enforced Stage-III measures on Friday, anticipating a worsening situation. However, the agency flagged poor compliance and incidents of open burning as major contributors to the pollution spike. Officials noted multiple reports of garbage and biomass burning from residential and industrial clusters, which exacerbated the air quality crisis.
The agency stressed that strict enforcement of bans on open burning and dust control at construction sites is critical. CAQM also appealed to citizens to adhere to GRAP measures aimed at improving AQI. These steps are essential for mitigating health risks and environmental damage.
Weather Conditions and Forecast
According to the Air Quality Early Warning System by IITM, severe conditions are likely to persist until January 18. Very poor air quality levels are expected between January 19 and 20. The system explained, "Ventilation index is likely to be 1,000 m2/s on Jan 18; 1,000 m2/s on Jan 19 and 4,500 m2/s on Jan 20 over Delhi." A ventilation index lower than 6,000 m2/s with average wind speed less than 10 kmph is unfavorable for pollutant dispersion. Overall, air quality is predicted to remain in the very poor category over the next six days.
Meanwhile, Delhi experienced a hazy day with brief periods of sunshine. The minimum temperature dropped to 4.4 degrees Celsius, three notches below normal. In contrast, the maximum temperature reached 24.6 degrees Celsius, five notches above normal. Moderate fog reduced visibility to 350 meters at Palam and 250 meters at Safdarjung in the morning, though flight operations remained unaffected. The IMD issued a yellow alert for dense fog in isolated areas. For Sunday, temperatures are likely to hover around 21-23 degrees Celsius (maximum) and 4-6 degrees Celsius (minimum).
