Deepavali fireworks send Delhi air quality inching to a five-year low, Pg1

Key Highlights:

• Delhi's air quality post-Deepavali 2025 neared a five-year low, with PM 2.5 levels exceeding 400 µg/m³, a level unseen since 2021.
• On Deepavali, 9 out of 293 cities monitored by the CPCB reported an AQI above 300, indicating ‘very poor’ air quality, which increased to 16 cities the day after.
• Dharuhera in Haryana recorded the worst AQI in the nation at 462 on the day following Deepavali.
• Despite the Supreme Court's allowance of only CSIR-validated ‘green crackers’, norms were seemingly violated due to the high volume of fireworks.

Detailed Insights:

• Climate Trends' analysis showed a sharp spike in PM 2.5 concentration in Delhi from 4 p.m. on Deepavali, reaching nearly 650 by 11 p.m., coinciding with permitted firecracker usage.
• Low wind speeds and warm temperatures ranging from 23-25 degrees Celsius on Deepavali night hindered the dispersal of smoke and pollutants in Delhi and the Gangetic plain airshed.
• In 2023, Delhi's post-Deepavali AQI was 358 (very poor), close to the 351 (very poor) reported at 4 p.m. in 2025, while the five-year high was 462 (‘severe’) on November 5, 2021.
• Data suggests that burning 'green' crackers made no measurable difference compared to regular ones, indicating that allowing firecrackers during this time is unsustainable for the NCR's air quality.

Key Concepts Involved:

• PM 2.5: Fine particulate matter with a diameter of 2.5 micrometers or less, a major air pollutant.
• AQI (Air Quality Index): A scale used to measure and report air quality, with different values indicating varying levels of pollution.
• Green Crackers: Firecrackers designed to emit less pollution compared to traditional ones, validated by CSIR.