New Delhi, Nov. 20 -- Only three cities in the country were in the throes of "severe" air on Wednesday - Ghaziabad, Greater Noida and Noida - while Delhi hovered just short of the danger zone, missing the threshold by only nine points as a thick, immovable haze settled across the National Capital Region (NCR).

Data from the Central Pollution Control Board (CPCB) showed Ghaziabad topping the national pollution charts with an air quality index (AQI) reading of 422, plunging it deep into the "severe" category. Greater Noida followed at 420, with Noida close behind at 409. Delhi's 4pm reading stood at 392 - "very poor", but alarmingly close to the next stage.

In fact, all 10 of India's most polluted cities on Wednesday were part of NCR, und...