Stage 4 of GRAP has been invoked in Delhi as AQI continued to worsen (File)
A thick layer of smog - a toxic blend of smoke and fog - enveloped the Delhi-National Capital Region (NCR) this morning as the air quality index (AQI) plummeted to the "severe-plus" category, forcing authorities to announce stricter pollution control measures.
Smog also affected visibility in the national capital, which hit flight operations and train services. Visibility at Palam dropped to 150 metres at 5 am.
According to the real-time data provided by the System of Air Quality and Weather Forecasting and Research (SAFAR), the AQI in Delhi was recorded at 481 at 7 am, the worst so far this season. Officials said it was due to "unfavourable" meteorological conditions in Delhi-NCR.
An AQI between 0 and 50 is considered good, 51 and 100 satisfactory, 101 and 200 moderate, 201 and 300 poor, 301 and 400 very poor, 401 and 450 severe, and above 450 severe-plus.
The Centre's air quality panel has invoked stricter pollution control measures for the Delhi-NCR under Stage 4 of the anti-pollution plan Graded Response Action Plan (GRAP), which have come into effect from 8 am. This is in addition to the preventive actions announced under Stage 1, Stage 2 and Stage 3 of GRAP already in force.
The GRAP for Delhi-NCR is divided into four stages of air quality: Stage 1 for "poor" air quality (AQI ranging from 201 to 300), Stage 2 for "very poor" air quality (AQI from 301 to 400), Stage 3 for "severe" air quality (AQI from 401 to 450), and Stage 4 for "severe-plus" air quality (AQI above 450).
The panel - Commission for Air Quality Management (CAQM) - has urged the public, particularly children, senior citizens and those with respiratory, cardiovascular, cerebrovascular or other chronic diseases, to stay indoors.
GRAP 4 In Delhi As Air Quality Worsens
Under Grap 4, no trucks will be allowed into Delhi except for those carrying essential items or using clean fuel (LNG/CNG/BS-VI diesel/electric). Non-essential light commercial vehicles registered outside Delhi will be prohibited, except for EVs and CNG and BS-VI diesel ones and those carrying essential items.
Delhi-registered BS-IV or older diesel medium and heavy goods vehicles are banned, except for those in essential services.
In-person classes have been suspended for all except for students in classes 10 and 12.
All construction activities, including highways, roads, flyovers, power lines, pipelines and other public projects, have been suspended.
Public and private offices in Delhi-NCR have been recommended to work at 50 per cent capacity, with the rest working from home. Work-from-home options may also be introduced for central government employees.
State governments could also close colleges, limit non-essential commercial activities and implement odd-even vehicle rules.
Around 38% of the pollution in the national capital this year has been caused by stubble burning or farm fires in the neighbouring states of Punjab and Haryana.
Delhi grapples with smog each winter as cold air traps dust, emissions and smoke from illegal farm fires.