Delhi ranked as the world’s most polluted major city on Friday, November 13, after its Air Quality Index reached 334 on the scale used by Swiss monitoring group IQAir. The reading put the Indian capital ahead of Lahore, Pakistan, in IQAir’s ranking, according to DW.
India’s Central Pollution Control Board recorded Delhi’s AQI at 403 and classified it as “severe.” The higher figure does not directly conflict with IQAir’s reading: the two organizations use different scales and methods to calculate and categorize air pollution.
The ranking reflects readings from Friday, rather than a fixed position over a longer period. IQAir’s hourly data showed Delhi’s AQI at 208 at 11:30 a.m. local time. At that point, Lahore’s reading was 155 and the Pakistani city stood seventh among the major cities in the ranking, NDTV reported.
Thick smog reduced visibility in parts of Delhi as pollution rose during the winter season. Across northern India and Pakistan, cold, heavy air can trap emissions from vehicles, dust from construction and smoke from agricultural burning, contributing to recurring seasonal pollution.
The figures describe different snapshots and measurement systems. IQAir’s 334 reading and the CPCB’s 403 rating both indicated severe pollution, but they should not be treated as directly comparable values on a single scale.
Reid Bentley