The AQI in Delhi-NCR is in the ‘severe plus’ category. AQI between 0-50 is considered “good”, 51-100 is “satisfactory”, 101-200 is “moderate”, 201-300 is “poor”, 301-400 is “very poor”, 401-500 is “severe” and above 500 is a “severe plus”.

A day after implementation of restrictions under Stage IV of the Graded Response Action Plan (GRAP) in the national capital region of Delhi, the Air Quality Index (AQI) in Delhi marginally dipped to 476 at 12 noon Tuesday from 495, recorded at 9 pm Monday.

The average air quality index (AQI) in Delhi early Tuesday was recorded to be 492 (as of 7 am). The AQI in Alipur, Anand Vihar, Bawana, Narela, Pusa and Sonia Vihar, meanwhile, touched 500, which is the maximum index (as per the Central Pollution Control Board).

The residents of Delhi-NCR woke up to severe cold, haze, and 'hazardous' air quality on Tuesday, with most AQI stations touching 500-mark (severe plus). According to the Central Pollution Control Board (CPCB),

India's capital city of Delhi has virtually shut down as air pollution hit "severe plus" levels, according to Indian government officials in its pollution control authority.

Delhi recorded air pollution more than 17 times above an acceptable level as worsening smog triggered curbs on trucking and shuttered construction sites and schools.

As toxic air blanketed Delhi on Monday morning, the Air Quality Index (AQI) in several areas of the city crossed the 1500 mark. This alarming spike in pollution levels has made Delhi the most polluted city in the world,

Till Saturday, a majority of Delhi’s pollution load was from stubble fires (25.10%), followed by vehicular emission (12.58%), & contamination from neighbouring states.

The CPCB advised people to minimise travelling during the hours when AQI is in the ‘severe’ or ‘poor’ category.