Delhi is world's 2nd most polluted city, AQI recorded at...

Delhi's air quality turned 'severe' for the first time this season on Wednesday, with the AQI soaring to 418. The national capital also became the world's second most polluted city in Swiss group IQAir's live rankings with an AQI of 427 on Thursday.

Delhi's air quality remained 'severe' for a second consecutive day, prompting the central pollution watchdog to invoke restrictions under the third stage of GRAP, including a ban on construction activities and plying vehicles on BS-III petrol and BS-IV diesel vehicles in the city and NCR. The restrictions will come into force at 8 am on Friday. 

The city's 24-hour Air Quality Index (AQI), recorded at 4 pm every day, stood at 424, up from 418 the previous day. Under the third stage of the Graded Response Action Plan (GRAP), all inter-state buses from NCR states -- except electric vehicles, CNG vehicles and BS-VI diesel buses -- will be prohibited from entering Delhi, alongside a stringent ban on construction and demolition activities, mining-related activities are suspended, water is sprinkled on major roads daily and students upto class 5 can be considered for online classes.

An AQI between zero and 50 is considered 'good', 51 and 100 'satisfactory', 101 and 200 'moderate', 201 and 300 'poor', 301 and 400 'very poor', 401 and 450 'severe' and above 450 'severe plus'. Of the 36 monitoring stations in Delhi, 30 reported air quality in the 'severe' category, according to the Central Pollution Control Board (CPCB).

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