Children are at higher risk, as pollution impairs lung development. The concentration of fine particles, known as PM 2.5, was 523 mg per cubic meter, which is 104.6 times higher than the recommended WHO guidelines. Long-term exposure to these particles, which are about 30 times thinner than a human hair and can enter the bloodstream through the lungs, have been linked to chronic heart and respiratory diseases. Dinesh Raj, leading pediatrician at the Holy Family Hospital in New Delhi, reports an increase in coughing in children, with an increasing number of children with asthma being admitted to the hospital due to acute exacerbation.

"Even infants are brought in for outpatient treatment due to respiratory complaints," he says, adding that children with respiratory infections exhibit more severe symptoms that take longer to calm down. Air pollution from a variety of sources, including road traffic, construction sites, and biomass burning in agricultural states, contributed to nearly 1.7 million deaths in India in 2019, reports the medical journal The Lancet. Children are particularly at risk as air pollution hampers their lung development and increases the mortality risk for children under five years old.

Children in New Delhi will not go to school this week as the government has taken urgent measures to protect its youngest residents from exceptionally high, toxic air quality. The air quality index reached a value of 565 in some areas and New Delhi was, therefore, the most polluted city in the world on Friday morning, according to the monitoring company IQAir.

The regional committee for air quality management has activated a crisis plan, which, among other things, provides for the suspension of construction projects, the use of public transportation, and working from home where possible. Normally, the air quality in Delhi deteriorates between October and November due to a mixture of factors such as weather patterns, emissions, and low temperatures preventing pollutants from dispersing. Mumbai is also experiencing high pollution, which prompted the Indian Cricket Association to ban traditional fireworks during the ongoing Cricket World Cup, reports the Indian Express.

On Friday, Lahore in India's neighbouring country Pakistan was the second most polluted city in the world with an air quality index of 335.

As Asia remains a hotspot for pollution, concerns grow over the health impacts of poor air quality worldwide, with similar pollution levels occurring in major cities across the U.S. and Canada due to wildfires, a trend expected to become more frequent due to climate change.