Delhi's air quality index (AQI) crossed the 300-mark on Diwali morning (October 20) and peaked at 451 ('Severe') by the next morning, despite GRAP Stage II restrictions being in place since October 19. PM2.5 concentrations reached 262 micrograms per cubic metre, over 59 times the WHO's annual guideline. Around 20 million residents woke up breathing the most polluted air of any major city globally. Out of 38 CPCB monitoring stations, 36 recorded air quality in 'very poor' to 'severe' conditions. Factors included Diwali fireworks, stagnant atmospheric conditions, and crop-residue burning in neighbouring states. Despite bans, non-green firecrackers were widely used past the permitted hours.
Delhi Air Quality Plummets to 'Severe' Category on Diwali Night
AQuick answer
Delhi AQI peaked at 451 (Severe) post-Diwali with PM2.5 levels 59 times above WHO guidelines despite GRAP-II restrictions.
Key facts
- Delhi AQI peaked at 451 (Severe) morning after Diwali despite GRAP Stage II restrictions since October 19
- PM2.5 reached 262 micrograms per cubic metre — 59 times WHO annual guideline
- 36 of 38 CPCB monitoring stations recorded very poor to severe air quality
- Factors: Diwali fireworks, stagnant atmospheric conditions, and crop-residue burning in neighbouring states
- Non-green firecrackers widely used past permitted hours despite bans
Mains angle
Q: Critically examine Delhi's air quality collapse to 'Severe' (AQI 451) with PM2.5 at 262 μg/m³ on Diwali night and evaluate the limitations of India's episodic pollution governance.
Answer (50 words):
Delhi's AQI crossed 300 on Diwali morning October 20 and peaked at 451 ('Severe') next morning, with PM2.5 reaching 262 micrograms per cubic metre — over 59 times WHO guidelines. Around 20 million residents breathed hazardous air, and 36 of 38 CPCB stations recorded very poor to severe levels despite GRAP-II enforcement.
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Linked questionMedium
On Diwali night 2025, Delhi's Air Quality Index (AQI) peaked at which level, categorised as 'Severe'?
Explanation · Correct answer C
Delhi's AQI crossed 300 on Diwali morning (October 20) and peaked at 451 ('Severe') by the next morning. PM2.5 concentrations reached 262 micrograms per cubic metre, over 59 times the WHO's annual guideline. Out of 38 CPCB monitoring stations, 36 recorded 'very poor' to 'severe' conditions.
Source: Al Jazeera
Frequently asked questions
What was Delhi's AQI on Diwali night 2025?
Delhi's AQI peaked at **451 (Severe category)** the morning after Diwali 2025 (October 20). Despite **GRAP Stage II restrictions** being in place since October 19, PM2.5 concentrations reached **262 micrograms per cubic metre — 59 times WHO's annual guideline**.
How many CPCB monitoring stations recorded severe air quality in Delhi during Diwali 2025?
**36 out of 38 CPCB monitoring stations** in Delhi recorded air quality in the 'very poor' to 'severe' categories during Diwali 2025. Around **20 million residents** woke up breathing the most polluted air of any major city globally.
What GRAP restrictions were in place during Diwali 2025 in Delhi?
**GRAP Stage II** restrictions were in place since October 19, 2025, including bans on coal/firewood in restaurants and enhanced road sweeping. Despite these measures, Delhi's AQI peaked at **451 (Severe)** with PM2.5 at 262 micrograms per cubic metre.
What are the main causes of Delhi's post-Diwali air pollution?
The main causes of Delhi's post-Diwali severe air pollution are: **Diwali fireworks, stagnant winds (low wind speed trapping pollutants), stubble burning in neighbouring states**, and unfavourable meteorological conditions. These factors combined caused AQI to peak at 451.
How does Delhi's Diwali AQI compare to WHO guidelines?
During Diwali 2025, Delhi's **PM2.5 concentration reached 262 micrograms per cubic metre**, which is **59 times higher than WHO's annual guideline**. The AQI peaked at 451 in the Severe category (401-500), making Delhi the most polluted major city globally on that day.
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