Taste of what lies ahead as Delhi’s AQI hits ‘poor’
Delhi's air quality worsened to 235 AQI, marking its worst level in 99 days, as pollution from stubble burning and dry winds begins to surge. And so it begins, like clockwork. Delhi’s air quality index (AQI) on Wednesday surged past the 200 mark and settled at 235, its worst level in 99 days as dust, dry winds, and the effect of crop stubble being burnt in Punjab heralded the arrival of the national capital’s dreaded annual pollution blight. The routine is now familiar and Wednesday was only an appetiser, although rain later in the week is expected to offer a marginal, and temporary, respite. For the next three months, perhaps more, Delhi’s 20 million-plus residents will inhale lungfuls of toxic air with every breath. Dipping temperatures, slowing winds and smoke from stubble fires in upwind Punjab and Haryana will drive up pollution levels to the worst in the world. The skies will turn grey, silhouettes will blur, and administrative collapse will be on display as authorities turn to the methods that have failed year after year. Wednesday’s AQI was, to be sure, down to only a fraction of the usual factors – local emissions, a six-day dry spell and nearly still winds. But with stubble fires already peppering the farmlands of Punjab, cultivators expecting a bumper paddy crop, the wind direction set to turn northwesterly and temperatures likely to dip, experts warned that Delhi’s problem will only get more acute in the weeks to come. In fact, this is the earliest the city’s post-monsoon AQI has dipped into the “poor” zone (a reading between 201 and 300) in six years. In 2018, the AQI passed 200 on September 29 (219). Last year, it crossed that threshold only on October 6 (212). The year before that, it happened on October 16 (232), and in 2021 on October 7 (215). Delhi’s AQI was last higher on June 19, when the reading hit 306. The Central Pollution Control Board (CPCB) categorises pollution levels on an ascending band between 0 and 500. It categorises readings between 0 and 50 as “good”, 51 and 100 as “satisfactory”, 101 and 200 as “moderate”, 201 and 300 as “poor”, 301 and 400 as “very poor” and above 401 as “severe”. The city’s air has tumbled in recent days, buoyed largely by the absence of rains, which kept pollution in check for nearly four months from early June. The AQI first worsened to 116 on September 21, then 164 on September 22, 167 on September 23 and 197 on September 24. Weather scientists pinned this sustained dip to calm winds and lack of rain. “Winds were calm overnight and with no rain, we are gradually seeing a rise in pollution as pollutants accumulate in the Capital. During the day, you are also seeing dust upliftment as the soil is again dry,” said Mahesh Palawat, vice president at Skymet meteorology. However, they underscored that the spike was not an aberration fuelled by atypical weather conditions, but rather a preface to the weeks of laboured breathing that lie ahead. Anumita Roychowdhury, executive director, research and advocacy at the Centre for Science and Environment said that in the absence of rain, Delhi starts to see a spike in pollution from October, aided by adverse meteorological conditions. “We see a dip in wind speed, little to no rain and low temperatures, all of which negatively impact AQI,” she said.