Three Indian cities ranked among the top four entries in IQAir’s live major-city air-quality table on Oct. 24, while NDTV Profit reported a different order a day earlier.
On Oct. 24, Mumbai ranked second with a U.S. AQI⁺ reading of 188. Kolkata was third and Delhi fourth, both at 181; Dakar ranked first at 870. IQAir did not specify the timestamp’s time zone.
NDTV Profit’s Oct. 23 report listed Dakar at 194, Lahore at 184, Kolkata at 177, Delhi at 168 and Mumbai at 165. In that report, Kolkata was third, Delhi fifth and Mumbai seventh. The outlet did not identify when those measurements were taken. IQAir says its live ranking refreshes at least hourly, so readings can differ between snapshots.
The live list includes roughly 120 major cities. IQAir calculates each city’s displayed AQI as the median across monitoring stations, and refreshes the list at least once an hour. The company also publishes separate annual rankings based on PM2.5.
IQAir classifies U.S. AQI⁺ readings from 151 to 200 as “Unhealthy.” India’s Central Pollution Control Board (CPCB) uses a separate National AQI, where readings from 101 to 200 are “Moderately polluted.” The two scales are not interchangeable.
