Breathing air in Delhi is like smoking 25 cigarettes a day: Can it cause cancer?

Delhi's air quality has reached hazardous levels, with pollution equated to smoking 25 to 30 cigarettes a day, reducing life expectancy and increasing cancer risks.

In Short

• Delhi's air is equivalent to smoking 25 to 30 cigarettes daily
• New study links air pollution to head and neck cancers
• Most lung cancer cases in India are linked to air pollution and genetics

India's national capital has been choking as it is covered with toxic haze. The poisonous PM 2.5 level in New Delhi has been around 247 µg/m3, which is way above the recommended guideline of 15 µg/m3 by the World Health Organisation. The Air Quality Index (AQI) has been soaring above 400, reaching the "hazardous" level, leaving citizens with persistent cough, watery eyes and fever.

Several lung diseases like COPD (Chronic obstructive pulmonary disease), bronchitis, rhinitis and pneumonia are majorly caused by polluted air that contains high amounts of particle matter, ozone, sulphur dioxide, carbon monoxide and nitrogen dioxide.

Lung specialists have said that breathing air in Delhi is equal to smoking 25 to 30 cigarettes a day, which is poisoning for people with healthy lungs. A report by the University of Chicago revealed that air pollution is reducing the life expectancy of Delhi residents by 7.8 years.

Long-term exposure to high levels of air pollution has been conclusively linked to an increased risk of lung cancer mortality. In fact, a report published by a US-based NGO, the Health Effects Institute, revealed that there have been 30 to 50% increases in lung cancer rates associated with exposure to respirable particles.

But new research is proving that air pollution isn't just limited to lung cancer, a study published earlier this week explores cancer risk that pollution may pose to the upper airway, specifically head and neck cancer.

"Head and neck cancer is a harder link to show, and it has a much lower occurrence than lung cancers, but since they also occur as a result of smoking, similar to lung cancers, we wanted to explore any connections," said John Cramer, the study's lead researcher.

He added, "Presumably, the link to head and neck cancer comes from what we breathe to that material affecting the lining in the head and neck. We see a lot of occurrences of where carcinogens touch or pool in the body to where cancers can occur."

Cramer observed the highest association between this type of pollution exposure with head and neck cancer after a five-year lag period. They focused on PM2.5, which is particulate matter measuring less than 2.5 microns, and its effect on head and neck aerodigestive cancer incidence.

Researchers from Tata Memorial Hospital, Mumbai, who published their study in July this year, found that most people who had lung cancer in India never smoked. In fact, genetic makeup and air pollution were big drivers with an incidence rate of 7.7 per 1,00,000 in 2019.

To lower this rate, experts are suggesting using air purifiers at home, wearing masks like N95 or N99 when stepping out, practising proper hygiene and staying hydrated.