Worsening Air Quality Forces Delhi-NCR to Escalate Curbs Twice in One Day

Delhi-NCR witnessed a rapid escalation in pollution control measures as authorities tightened restrictions twice within a single day. With air quality deteriorating sharply on Saturday, the Commission for Air Quality Management (CAQM) first imposed GRAP Stage 3 measures and, within hours, escalated them to the strictest Stage 4. The move followed a steep rise in the Air Quality Index, raising public health concerns across the region.

AQI Surge Triggers Swift Action

The decision was driven by a sudden spike in pollution levels. The AQI crossed 400 by afternoon, entering the ‘Severe’ category, prompting the implementation of GRAP-3. By evening, readings climbed further from 431 at 4 pm to 441 at 6 pm, approaching the ‘Severe Plus’ threshold. Observing the upward trend, the CAQM invoked all actions under GRAP-4 with immediate effect across the entire National Capital Region.

Meteorological Factors Behind Worsening Air

Authorities attributed the sharp decline in air quality primarily to unfavourable weather conditions rather than a sudden rise in local emissions. A weak Western Disturbance over north-west India led to low wind speeds, frequent calm conditions, and a shift in wind direction. Increased moisture in the lower atmosphere further contributed to smog and fog formation, trapping pollutants close to the ground and severely reducing dispersion.

Key Restrictions Under GRAP Stage 4

Stage 4 introduces the most stringent curbs to limit pollution sources and reduce public exposure. Entry of non-essential trucks into Delhi is banned, with exemptions only for vehicles carrying essential goods or using cleaner fuels such as CNG, LNG, electric, or BS-VI diesel. Older diesel-operated medium and heavy goods vehicles registered in Delhi are prohibited, except for essential services. All construction and demolition activities, including major infrastructure projects, are halted.

Exam Oriented Facts

• GRAP stands for Graded Response Action Plan.
• Stage 4 is invoked when AQI exceeds 450 or shows a rising severe trend.
• The Commission for Air Quality Management oversees pollution control in Delhi-NCR.
• Western Disturbances can significantly affect winter air quality in north India.

Impact on Offices, Schools and Daily Life

To minimise exposure, state governments may shift physical classes for students in Classes VI to IX and XI to online mode. Offices are advised to operate with at least 50% staff working from home, along with staggered timings to reduce traffic congestion. Authorities may also consider additional emergency steps, including closure of colleges, suspension of non-essential commercial activities, or implementation of odd-even vehicle schemes if conditions worsen further.