‘Pollution A Silent Killer, Air Purifiers May Not Protect You’: Dr Randeep Guleria

News india ‘Pollution A Silent Killer, Air Purifiers May Not Protect You’: Dr Randeep Guleria

Last Updated:October 28, 2026, 10:06 IST

The former AIIMS director advised people to wear N-95 masks during bad air quality days, noting that air pollution worsens underlying conditions and kills quietly

Air purifiers have not been conclusively shown to protect people from Delhi’s toxic air, and children growing up in it are suffering stunted lung growth that can recover if air quality improves, Dr Randeep Guleria, former director of the All-India Institute of Medical Sciences (AIIMS), has said in an interview to CNN-News18.

Advising people to wear N-95 masks during bad air quality days, Guleria said: “A well-fitted mask that forms a tight seal over the nose and mouth does offer some protection." On air purifiers, however, he was more cautious. Many studies have failed to conclusively show that they are very useful, he said, adding that he would not deem them very effective.

Guleria explained that their performance depends heavily on the room as doors and windows left open allow pollutants in. In a large room, a purifier kept at one end cannot clean the air at the other.

Calling air pollution a “silent killer", he said the biggest challenge is that it never appears as a cause of death. “A person who dies of dengue or swine flu is recorded as such, but a death certificate does not say the person died of pollution." Air pollution worsens underlying conditions and kills quietly, he said, noting that policymakers need to understand the cause and effect.

Children’s Lungs At Risk, But Recovery Possible

When asked about the impact of worsening air quality on the health of children and infants, Guleria, who is now chairman of the Institute of Internal Medicine and Respiratory & Sleep Medicine, Medanta Hospital, said the lungs keep growing through childhood and even teenage years, both in size and in the number of tiny air sacs.

“Studies show that children growing up in polluted areas are affected because the lungs continue to grow during childhood. Studies suggest that our lungs continue to grow as we gain height, and even in our teenage years. There is lung growth, not only in size but also in the number of alveoli. When children are growing up in areas where pollution levels are high, this growth gets stunted. And there are studies which clearly show that lung function is lower in children growing up in areas where pollution is high as compared to children who grow up in areas where pollution levels are low."

However, there is some hope, he said. A recent follow-up study from the United States found that when air quality improved, children’s lung function improved too, because their lungs were still growing. That is why, he said, urgent action is needed now. He pointed out that this is not only a Delhi problem. Large parts of north and central India face very poor air on most days of the year, while children continue to play outdoors and go to school.

Are Indian Lungs Really Black?

Asked whether Indians really have black lungs, the country’s top pulmonologist said people who live for years in highly polluted areas breathe in carbon particles, or soot, which get deposited in the lung tissue and darken it.

“So, for people living for years in areas where pollution levels are high, carbon particles or soot, as we call it, which is part of the pollutants, get deposited in the alveoli, or in the lung tissue, and lungs therefore become darkened in colour."

He added, “If you do procedures like what we call bronchoscopy, where you look inside the lungs from a tube, like an endoscope, you will find that the airways also have what is known as anthracotic pigment—black-coloured particles. It shows that the pigment starts getting deposited in the airways also. So, it’s not only the outer surface of the lung, but the inner tubes or the lining which takes air into our lungs also starts getting dark."

Fix Possible In 5-10 Years

On what the government must do, Guleria called for practical policies backed by yearly timelines, such as bringing down the AQI by a fixed number of points every year. He said this could work in “5 to 10 years". He cited the London smog of the 1950s, Los Angeles and Beijing, which were heavily polluted around the Olympics but now have much better air.

“We have enough studies now" showing both short-term and long-term harm from air pollution, he said. “The challenge now is implementation."

About the Author

Himani ChandnaSenior Associate Editor

Himani Chandna, Senior Associate Editor at CNN-News18, tracks healthcare, pharma and medical research, bringing clarity to complex science and policy.

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