Delhi Chokes Again: 'Severe' Smog Covers City, Schools on High Alarm as AQI Reaches Hazardous Levels
Delhi residents woke up Thursday to hazardous air pollution readings, with thick smog covering the city and reducing visibility substantially. The Air Quality Index in the national capital breached the "severe" category after it recorded the worst AQI this season. On Wednesday, pollution levels shot up dramatically, taking AQI in most areas of Delhi well beyond 400 and into the "severe" category. In early Thursday morning, Anand Vihar clocked an AQI at 473, while Aya Nagar, Ashok Vihar, and Wazirpur also reported severe levels of pollution.
The CAQM hasn't yet issued Stage 3 of the Graded Response Action Plan (GRAP), which means all the restrictions, including suspending physical classes of primary school students and stopping all construction work, haven't been implemented. It said that the prevailing wind pattern would help disperse pollutants, and conditions were likely to improve towards the fag end of this week. However, authorities asserted they would keep a close eye on the situation and invoke strict measures if pollution continues unabated.
High Levels of Severe AQI and GRAP Stages
By Wednesday, Delhi AQI levels had reached as high as 454 in the evening, up from an average of 418 in the afternoon. The city witnessed a first dense fog of the season and also colder temperatures with this which trapped pollutants close to the ground, causing a steep rise in AQI levels. Pollution control board has termed it an "episodic event.".
The CAQM may continue Stage 3 of GRAP if Delhi's air quality deteriorates and the air quality remains very poor. The measure includes stopping all construction and demolition activities, all physical classes for students up to Class 5, and encouraging alternative modes to reduce reliance on polluting modes and emissions.
Stage 2 of GRAP was invoked yesterday. It will remain valid for the time being as of now.
Temperature Sinks and Inter-State Comparisons
The maximum temperature at Delhi decreased from 32.8°C on Tuesday to 27.8°C on Wednesday, that made the fog more intense and trapped the pollutants inside. Data published by the Central Pollution Control Board indicated that 30 of the 36 monitoring stations in Delhi had "severe" air quality. That is, the smog infected the entire area, and it came second only in the AQI because of the city of Hajipur in Bihar that also touched 417.
AQI and Health Implication
The scale is between "good" at 0-50 to "severe plus" at 450+. High levels of severe AQI over an extended period may trigger respiratory issues in many, especially the children, elderly, and others. Then authorities may turn to more extreme measures to mitigate exposure as pollution remains high.
Delhi has faced repeated air quality challenges over the past several months, and experts said they are keeping an eye on the situation. Stricter restrictions are likely to come into effect if the air quality does not improve, meaning that efforts by CAQM to walk the tightrope between health risks and logistical concerns will be of utmost importance to the city's crisis of air pollution.
