Daijiworld Media Network - New Delhi

New Delhi, Nov 13: Delhi overtook Pakistan's Lahore to emerge as the world's most polluted major city on Friday, as air quality plunged to hazardous levels and thick smog enveloped the national capital, reducing visibility across the city of around 20 million people, Reuters reported.

According to Swiss air quality monitoring group IQAir, Delhi recorded an Air Quality Index (AQI) of 334, placing it at the top of the global list of major cities with the worst air quality. The organisation categorised the reading as 'hazardous', reflecting the high concentration of harmful pollutants in the air.

An AQI reading of up to 50 is considered good, indicating little or no health risk.

India's Central Pollution Control Board (CPCB), however, recorded an even higher AQI of 403 for Delhi and classified the air quality as 'severe', highlighting the extent of pollution affecting the capital.

The difference between the readings reported by IQAir and the CPCB is attributed to the different AQI scales and methodologies adopted by the two agencies to measure and classify air pollution levels.

The worsening conditions were evident across the city, with dense smog reducing visibility on major roads. Videos shared by news agency ANI showed cars and motorcycles moving through thick layers of haze, while streetlights along some of the capital's main roads appeared obscured by the pollution.

Air pollution is a recurring seasonal concern across several parts of northern India and neighbouring Pakistan, particularly during the winter months. Cold, heavy air tends to trap pollutants close to the ground, preventing their dispersal and causing pollution levels to rise.

Vehicle emissions, construction dust and smoke from agricultural burning are among the major contributors to the seasonal deterioration in air quality across the region.