A report from Swiss air quality technology company IQAir indicated that 83 of the 100 cities with the worst air pollution in the world were in India in 2023 (CNN). The question will be suspended on 29 September 2024 and the outcome determined using data from AirNow once complete data for the month of September 2024 are available (AirNow.gov). To access the resolution data on the site, choose "New Delhi" under "Select a City," click on the "Historical" tab, and download the file for "2024 PM2.5 YTD." Add all positive valid data points for the column titled "AQI" (invalid entries are coded as -999, and valid data points are labeled "Valid" under "QC Name") with an "9" under "Month" and divide the sum by the number of valid data points. Averages in September 2019, 2020, 2021, 2022, and 2023 were, respectively, 100.70, 117.08, 82.78, 94.55, and 98.84. If the named source changes the way it presents the data, we will make the appropriate modifications to the resolution instructions.

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The question closed "At least 90.00, but less than 100.00" with a closing date of 1 October 2024.

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