New Delhi, Nov. 15 -- Faster winds on Friday helped slightly improve Delhi's air quality, providing reprieve from three consecutive days of "severe" air and bringing it down to the upper-end of "very poor" air quality index (AQI), according to the Central Pollution Control Board (CPCB).

On Friday morning, the AQI was 395 ("very poor") at 9am, which further improved to a 24-hour average of 387 by 4pm, according to the CPCB's daily bulletin. The AQIs over the past three days were 428, 418, 404, all in the "severe" zone.

The CPCB classifies an AQI of 51 to 100 as "satisfactory", 101 to 200 as "moderate", 201 to 300 as "poor", 301 to 400 as "very poor", and a reading above 400 as "severe".

Mahesh Palawat, vice president at Skymet, a privat...