Capital punishment: Delhi air now 'severe'

City residents woke up on Wednesday to an all-too-familiar nightmare: a thick, choking haze of smog blanketing the city, laced with the acrid tang of pollution that signals the firm arrival of the Capital's annual "severe" air crisis slightly later than usual this year, but unrelenting as ever.

- Aheli Das

The Capital recorded a 24-hour average air quality index (AQI) reading of 418 at 4 pm, a sharp deterioration from 334 at the same time on Tuesday, according to data from the Central Pollution Control Board.

This rapid worsening showed no sign of stopping, with the AQI soaring to 452 by 11 pm, falling in comfortably "severe plus"—the worst possible category within the AQI range.

In fact, Delhi's AQI reading on Wednesday was the worst for any city in the country.

But even as residents struggled to breathe, the Commission for Air Quality Management (CAQM) refrained from implementing Stage 3 of the Graded Response Action Plan (Grap) -- in which schools are shut and all private construction is halted -- stating that the AQI will likely "improve" to the "very poor" zone by Thursday.

The abrupt worsening in pollution was largely down to meteorological conditions: a cocktail of stagnant winds, sudden lowering of temperatures, and dense smog worked together to trap pollutants over the city.

These same factors had so far this season been favourable, and had thus helped the city avoid the brunt of post-Diwali pollution.

For example, the bursting of firecrackers generally turns Delhi's air severe in the days following Diwali. But it did not happen this year (Diwali was celebrated on October 31) because faster winds cleaned up the pollutants from firecrackers.

The first severe AQI in 2023 was recorded on November 3 and November 1 in 2022.