India, Nov. 7 -- Delhi's official air quality index (AQI) hit 382 on Friday, the city's worst since January 19, and may still be understating pollution levels after 13 new stations were added to the monitoring network in October, an HT analysis of Central Pollution Control Board (CPCB) data has found. Without the new stations, Friday's 4pm bulletin would have read 393.

Most of the new monitors, set up by the Delhi Pollution Control Committee (DPCC), the city government's pollution regulator, are on the city's periphery, but older stations just as far out, in areas just as built-up, show much higher readings. HT's analysis found the levels of PM2.5 - the biggest contributor to pollution during the winter smog spell --- at the new stations...