From chronic cough, lung damage, and cancer risk, to cardiovascular issues, PCOS, and mental disorders, the list of health issues that can be directly traced back to air pollution keeps growing.

Studies have shown this damage begins even before a child is born.

And yet there are very few studies, particularly in India—home to one of the most populated cities in the world—that comprehensively establishes the impact of air pollution on kids' health.

This changes with a new landmark study which has found strong evidence linking air pollution to a distinctly higher risk of asthma and obesity in kids.

The extensive study published in the journal Lung India compares the health status of adolescent children in Delhi to those of Mysuru and Kottayam to see how the toxic air in Delhi impacts the kids' health in comparison to those in the other cities.

Before we dive into what the study found, let's looks at how the study was conducted.

Students in the Delhi schools were found to have a consistently higher prevalence of Asthma and allergy symptoms as compared to school children in Kottayam and Mysuru.

• 29.3 percent children from Delhi were found to have airflow obstruction or asthma on spirometry as compared to 22.6 precent children in Kottayam and Mysuru.

This was despite the fact that the two other significant variables associated with childhood asthma—family history of asthma, and smokers in the family—were more prevalent in Mysuru and Kotayam.

• Diagnosis of asthma was lower in the kids in Delhi, and even less got treatment.

The study also found a huge difference in the prevalence of asthma among boys and girls. But this was recorded in all three cities.

Dr Salvi hypothesises that it might have something to do with hormones, and not so much with pollution.

• The study also found that 39.8 percent children from Delhi were obese/overweight as compared to 16.4 percent children from Kottayam and Mysuru.

"We also found that children who were obese had much higher odds of developing asthma," said Dr Sundeep Salvi, Director, Chest Research Foundation (CRF), and one of the co-authors of the study, at the press conference.

• Obese and overweight children, the study found, had a 79 percent greater chance of having asthma on spirometry across all three sites combined.

• Air pollution seems to perpetuate this link between obesity and asthma as the association was found to be 38 percent higher in kids from Delhi as compared to those in Mysuru and Kottayam.

According to the study authors, particulate matter pollutants like PM2.5 and PM10 are the prime suspects for this connection.

According to Dr Kumar, the reason why children are more at risk of health complications from air pollution because "they breathe more than adults, and their lungs have growing tissues. There are many more variables that could impact the health of an adult."

The study authors also point out that it is easier to conduct such an extensive study on children through schools.

The study underscores the urgent need for action.

Prof Koul also talks about how all parents in Delhi (and cities with similar pollution levels) must b sensitised to the gravity of the situation and just how hazardous the air they're breathing is to their kids' health.