According to reports, more than 20 trains were delayed and at least eight flights diverted due to low visibility.

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”.

Northern India is grappling with a severe air quality crisis as pollution levels skyrocket across major cities. The situation is particularly dire in Delhi, Mumbai, and parts of Uttar Pradesh and Bihar, where the Air Quality Index (AQI) has reached alarming levels, posing significant health risks.

Residents in India's northern states woke up to another day of poor air quality on Tuesday, as a layer of dense fog shrouded most of the region, and pollution in the capital Delhi remained severe.

India, Delhi’s air quality index (AQI) on Tuesday morning stood at 492, which is worse than Monday’s 483. Monday’s 483 AQI was the season’s worst but Tuesday has plummeted further.

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,

With air pollution levels escalating to alarming levels in Delhi and the National Capital Region, the sale of air purifiers and masks have surged significantly, according to traders in the city

Delhi's 24-hour AQI, recorded at 4 pm daily, stood at 441, data from the Central Pollution Control Board (CPCB) showed.