Children are the main victims of the poisonous air in the Indian capital.

The toxic smog that shrouds the Indian capital, Delhi, is no more, but its children are reaping the brunt of the city’s deteriorating and recurring pollution problem.

Nowhere is this more evident than in paediatricians’ clinics. The BBC visited one such facility in Noida, near Delhi, a few days ago on a Saturday morning.

In the packed waiting hall outside the doctor’s consulting room, worried parents lined up as children complained of sneezing, coughing or breathing problems.

Most began to fall ill in October, when the capital’s air quality sank to substandard levels and waiting for a doctor’s appointment took longer than usual to make the flowers last longer.

Toxic air is a recurring problem in Delhi and parts of northern India during winters.

There is no single cause behind this problem, but a combination of factors such as low wind speeds in neighbouring states, industrial emissions, vehicle routes, falling temperatures, and the seasonal burning of crop poles.

Since last month, Delhi’s Air Quality Index (AQI) has hovered between 300 and 400, measuring various types of pollutants, including levels of fine particulate matter PM2.5 that can clog the lungs. This is more than 20 times the limit recommended by the World Health Organization.

Readings above 400 affect all healthy people and seriously affect those with existing illnesses, but high exposure to PM 2.5 hits children and the elderly the hardest.

Across the capital, many hospitals have seen an influx of children sickened by the relentless wind.

“These particles can affect a child’s immunity, especially because their system is still developing and cells are learning the immune response in the early years,” a paediatrician at the Noida Clinic told the BBC.

“These cases have increased tenfold in recent years. In my experience, if I usually see an average of 20-30% of patients with such complaints, this number increases to 50-70% during the pollution season.”

Every year, the government prepares emergency measures – to halt construction, to ban polluting vehicles – to curb smog. This year, he tried cloud seeding to trigger artificial rain without success.

But none of these actions has helped alleviate the pollution crisis that causes anxiety among the city’s 20 million people, especially parents of young children.

Khushboo Bharti, 31, says every time she remembers the night of November 13, when she had to rush her one-year-old daughter, Sameera, to the emergency room.

“I remember waking up with a violent cough that made him vomit several times,” says Ms Bharti.

He tried the usual home remedies, but nothing worked. Finally, she took the child to the hospital in the middle of the night.

“On the way there, Samira didn’t react to anyone or anything. It was just the opposite; she’s a bubbly baby. She wouldn’t even lift her head. It was the worst moment of my life.”

At the hospital, the toddler was treated with a strong steroid nebulisation and was on oxygen support for two days. He was later diagnosed with pneumonia.

Since then, Ms Bharti has been on constant edge.

“Even if he only coughs a few times, I panic.”

Sameera has now recovered, but other parents like Gopal*, who had to take her two-year-old daughter Renu* to a government hospital last week due to chest congestion, fear that the deadly air has irreversibly damaged their children’s health.

“The doctors told me he would have to be on the inhalers for a while,” Gopal told the BBC.

Research over the years has highlighted the devastating effects of air pollution on young children around the world. Air pollution stunts the development of young children worldwide. Weak immunity and low cognitive ability.

A recent study from the University of Cambridge included data on nearly 30 million people exposed to certain pollutants. There is an increased risk of developing various types of dementia, including Alzheimer’s disease.

These increased risks have forced many parents like Ms Bharti to consider moving out of Delhi.

“What’s the point of living in a city where my daughter can’t even breathe safely?” she asks. “My husband’s business is in Delhi, so we can’t leave everything and leave. But the moment we get a chance, we will move forward.”

For now, Delhi has moved to limit children’s exposure — postponing outdoor sports and shifting primary classes to hybrid mode.

The relatively privileged will benefit from them, but for hundreds of thousands of economically disadvantaged children, born into working-class families and living on the roadside or in shantytowns, “the attack on their lungs is enormous,” Dr A Fatehuddin, a pulmonologist based in Kerala, told the BBC.

Living in cramped homes exposes them to more pollution from cooking fuel, traffic and poor ventilation. And poisonous air spoils the exterior.

“These children are constantly exposed to high degrees of pollution so their lung defences are reduced. If you fail to treat such childhood infections, it can cause permanent lung damage,” says Dr Fatudin.

Several studies show how exposure of “naive lungs” to air pollution from early childhood infections can lead to chronic airway obstruction in adulthood, similar to that seen in smokers, he said.

Those who do should keep their children strictly indoors and ensure they are properly hydrated and wear N95 masks – which filter 95% of pollutants, says Dr Fatudeen.

But parents question how long they can keep children indoors.

“They are growing; they need space to play and when they get short moments in nature, we are now forced to stop them,” said one mother.

“They sometimes protest, but what choice do we have? We know how important physical activity is, but not at the cost of breathing this toxic air,” she says.