India's national capital, Delhi, overtook Pakistan's Lahore on Friday to become the world's most polluted city, as air quality deteriorated to hazardous levels. A thick layer of toxic smog covered the city, significantly reducing visibility and making it difficult for residents to breathe.
 

Delhi, which has a population of nearly 20 million, witnessed dense smog across several areas during the morning hours. Vehicles and motorcycles were seen moving through the thick haze on major roads, while the brightness of streetlights was also reduced due to poor visibility.
 

According to the latest data released by Swiss air quality monitoring platform IQAir, Delhi recorded an Air Quality Index (AQI) of 334. The reading placed the national capital in the 'Hazardous' category and at the top of the global list of the most polluted cities.
 

An AQI reading of up to 50 is generally considered good and safe for health, highlighting the seriousness of the pollution levels recorded in Delhi.
 

Meanwhile, India's Central Pollution Control Board (CPCB) reported an even higher AQI of 403 for the city, placing the air quality in the 'Severe' category.
 

Experts attribute the difference between the IQAir and CPCB readings to the different methods and scales used by the Swiss and Indian agencies to measure and classify air pollution.
 

Air pollution becomes a major seasonal challenge across large parts of northern India and neighbouring Pakistan with the arrival of winter. Cold and heavy air conditions prevent pollutants from dispersing, trapping vehicle emissions, construction dust and smoke from stubble burning close to the ground.
 

As a result, pollution levels rise, visibility deteriorates and breathing becomes increasingly difficult for people living in affected areas.
 

The latest readings underline the worsening air pollution situation in Delhi as winter sets in, with the capital facing hazardous air quality and a thick blanket of smog.