New Delhi, Dec. 16 -- Delhi residents woke up to a dense blanket of smog, as the air quality in the national capital remained at hazardous levels on Monday, with the city's 24-hour average air quality index (AQI) touching 427 - in the 'severe' category.
However, the readings improved slightly from Saturday's readings, which breached the 450 mark of the 'severe plus' category.
At 447, Greater Noida and Ghaziabad (444) emerged as the worst-polluted cities in the nation, replacing Noida, whose AQI showed a minor improvement and stood at 437 on Monday, as recorded by the 4 p.m. national bulletin of the Central Pollution Control Board (CPCB).
As per the CPCB classification, AQI levels above 400 fall in the 'severe' category, affect healthy pe...