Delhi’s AQI Surpasses 300 as Winter and Pre‑Diwali Pollution Spike

Delhi’s air quality index (AQI) has crossed the 300 mark, entering the “very poor” bracket that the nation’s pollution watchdog defines as readings between 301 and 400. On Wednesday morning the capital recorded an AQI of 377, a level that raises health concerns for millions of residents.

Prolonged exposure to such polluted air can trigger respiratory problems and aggravate existing illnesses, with children and the elderly identified as the most vulnerable groups.

In response, officials have invoked Stage II of the Graded Response Action Plan (GRAP). The plan escalates emergency measures as pollution worsens. Under the latest restrictions, the city is stepping up road cleaning, raising parking charges to deter private vehicle use, and boosting public‑transport capacity. Delhi Metro has added 20 weekday train trips, and government offices have been instructed to stagger timings to ease traffic congestion.

These actions were taken after forecasts indicated that the “very poor” air quality would persist for several days. The timing is notable because the city, along with surrounding northern Indian regions, typically faces hazardous winter air, especially around Diwali – a festival celebrated with lights and fireworks that further degrade air quality by emitting fine particles and harmful gases.

The current spike follows an unusually clean October, during which Delhi logged its lowest average AQI for the month in eight years. Experts attribute the rapid reversal to falling temperatures, low wind speeds and a rise in crop‑residue burning in the neighboring states of Punjab and Haryana. A recent storm had temporarily cleared the skies with rain and stronger winds, but as conditions settled, northwesterly winds returned, carrying smoke from burning fields toward the capital.

The AQI calculation incorporates eight major pollutants, including PM2.5 – particles about 30 times smaller than a human hair that can penetrate deep into the lungs. Readings above 400 would be classified as “severe”, a threshold not yet reached but looming if conditions do not improve.

With Diwali only days away, the city’s authorities face a dual challenge: managing the seasonal rise in pollution while trying to limit the additional impact of festival fireworks.