Noida: After two straight ‘poor’ air days, overnight showers washed out particulate matter and dust, bringing the air quality index (AQI) into the ‘satisfactory’ category in Noida and neighbouring Greater Noida and Ghaziabad for the first time in two weeks.Noida recorded 39mm of rain overnight and another 2.5mm until 5.30 pm on Friday. Following rain and thunderstorms, accompanied by winds of 10-15 kmph, the city’s AQI stood at 58 on Friday, in the ‘satisfactory’ category, which is significantly better than 222 on Thursday and 246 on Oct 28. On Oct 16, the city recorded an AQI of 83.Between Oct 24 and 27, the AQI stayed in the ‘moderate’ category, oscillating between 191 and 131. The city saw another ‘poor’ spell from Oct 21 to 23 — the worst reading of 249 came on Oct 21 amid low wind speed.On Friday, of the seven monitoring stations, Sector 1 recorded ‘good’ air at 44. Four stations in sectors 62, 116, 125 and 150 stayed in the ‘satisfactory’ category. Sector 116 recorded the highest AQI of 67, with carbon monoxide identified as the major pollutant. The two remaining stations could not pick up pollution data.Monitoring stations in Greater Noida could not pick up pollution data properly because of sudden and frequent changes in the weather. The only station that recorded data, Knowledge Park 3, showed an AQI of 59, with carbon monoxide again as the dominant pollutant.Ghaziabad fared even better, with its AQI improving to 55, just five points short of the ‘good’ category mark. Of the eight monitoring stations in the city, New Tehsil Loni recorded 68. One of the new stations added in the city, it recorded an AQI of 374 a couple of days ago. Three stations remained in the ‘good’ category — Sanjay Nagar recorded the cleanest air with an AQI of 20, against 170 on Wednesday. Wave City was the only station to see an AQI of 104 in the ‘moderate’ category.In Delhi, the average AQI of 167.2 this month was the lowest Oct reading ever, which was a result of a confluence of favourable factors, such as excess rainfall, a late Diwali and a low contribution of stubble burning to the emission load so far.The AQI of 167.2 was recorded after years of breaching 200 on the AQI scale — 223 in 2025, 234 in 2024, 219 in 2023, 210 in 2022. In 2021, the average Oct AQI was 173, which is still a few notches higher than this Oct. Data from Central Pollution Control Board shows that the average AQI was 265 in 2020, 234 in 2019, 269 in 2018, 285 in 2017, 271 in 2016 and 264 in 2015.However, the capital’s average PM2.5 and PM10 levels were still higher than the national standard. The PM2.5 concentration this month is 70.5 micrograms per cubic metre, when the daily national ambient air quality standard is 60 micrograms per cubic metre. It is also 4.7 times higher than WHO’s daily safe limit of 15 micrograms per cubic metre for PM2.5.Anumita Roychowdhury, executive director-research and advocacy, Centre for Science and Environment, sounded caution while explaining the reasons for the lower AQI. The excess rainfall throughout the month scrubbed ambient particulates while also aiding dispersion, she said. “This minimised the transboundary smoke contribution from regional farm stubble burning. Also this time, Diwali firecracker emissions are not impacting Oct’s air quality. While this drop offers relief, the improvement is largely meteorology-driven,” Roychowdhury said.She added that as winter approaches, dropping temperatures and atmospheric inversion will require rigorous ground-level action focused on transport, waste burning and industrial emission sources.The sudden change in weather was triggered by a western disturbance. A cyclonic circulation lay over north Punjab and its neighbourhood, and over north Haryana and its neighbourhood, at 4.5km above mean sea level, with a trough aloft in the middle and upper tropospheric westerlies. The trough now runs from northwest Uttar Pradesh to the cyclonic circulation linked to a low-pressure area over north Chhattisgarh and adjoining east Madhya Pradesh, southeast Uttar Pradesh and west Jharkhand, at 3.1km above mean sea level.The system is likely to bring overcast skies on Saturday, with light rain at isolated places in NCR and winds of 5-15kmph.
