Delhi Blanketed in Toxic Smog as AQI Hits Severe Levels; GRAP-4 Restrictions Enforced

New Delhi: The national capital awoke to a dense haze of smog on Sunday, with air quality plunging deep into the 'severe' category. According to the Central Pollution Control Board (CPCB), Delhi's overall Air Quality Index (AQI) stood at 462 early in the morning, with all 40 monitoring stations registering levels in the severe range.

Areas like Rohini in northwest Delhi recorded the highest AQI of 499, primarily driven by elevated PM2.5 concentrations, while Jahangirpuri and Vivek Vihar followed closely at 495. Reduced visibility forced motorists to switch on headlights even during daylight hours, as seen in visuals from Patparganj in east Delhi, where the AQI reached 488.

The AQI serves as a key indicator of air pollution, factoring in eight major pollutants including PM10, PM2.5, ozone, sulphur dioxide, nitrogen dioxide, carbon monoxide, lead, and ammonia. Categories range from 'good' (0-50) to 'severe' (401-500), with severe levels posing serious health risks, including advice to avoid outdoor activities.

Experts note that India's AQI scale caps at 500, grouping any higher readings under 'severe' to prevent public panic, even though calculations can exceed this threshold. While long-term exposure effects plateau at high levels, short-term spikes significantly heighten risks of hospitalisation for vulnerable groups, such as those with respiratory or heart conditions.

In response to the deteriorating conditions, the Commission for Air Quality Management (CAQM) escalated measures on Saturday, first invoking GRAP Stage 3 before advancing to the strictest Stage 4. Authorities attributed the sharp decline to a weak western disturbance, resulting in calm winds, directional shifts, and increased atmospheric moisture—conditions that trap pollutants and foster smog formation during winter.

Key restrictions under GRAP-4 include:

- Prohibition on non-essential truck entry into Delhi, except for those transporting essential goods or using clean fuels like LNG, CNG, electric, or BS-VI diesel.

- Ban on diesel-powered medium and heavy goods vehicles (BS-IV and below) registered in Delhi, barring essential services; similar curbs apply to light commercial vehicles from outside the city unless compliant.

- Complete halt on all construction and demolition activities, including public infrastructure projects.

- Option for states in Delhi-NCR to switch physical classes for students in Grades VI-IX and XI to online learning.

- Recommendation for offices to operate with at least 50% staff remotely and implement staggered timings to ease traffic congestion.

As the city grapples with this seasonal crisis, residents are urged to minimise outdoor exposure, with forecasts suggesting a possible minor improvement in the coming days due to changing wind patterns.

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