World Lung Cancer Day: Looking Beyond Tobacco

August 1, 2025

At our oncology centres in India, I am sure we all often come across a concerning trend— people diagnosed with lung cancer who have never smoked. These are often homemakers or professionals in their 40s or 50s, with no history of tobacco use, no known family history, and relatively healthy lifestyles. The first question that comes to my mind is: why?

Today, on World Lung Cancer Day, while global conversations rightly focus on tobacco as the leading cause of lung cancer, it's equally important to highlight the non-tobacco causes that are often overlooked, especially in low- and middle-income countries. Tobacco remains the biggest driver, but it is not the only villain in the story.

Air pollution, both indoor and outdoor, plays a silent but significant role. According to IQAir India is home to 11 of the 20 most polluted cities in the world. Prolonged exposure to fine particulate matter (PM2.5) and other pollutants increases the risk of lung cancer, even among non-smokers. According to the Global Burden of Disease report, air pollution contributes to nearly 15% of lung cancer deaths globally, a number likely underestimated in high-exposure regions.

Indoor pollution is another culprit—particularly in rural and semi-urban households where biomass fuels like wood, cow dung, and charcoal are still used for cooking. Women, being primarily responsible for domestic cooking in many parts of India, are exposed daily to smoke in poorly ventilated kitchens. Several studies have shown a higher incidence of lung cancer among non-smoking women in such environments. Unfortunately, this connection often goes unrecognized during diagnosis and prevention discussions.

Another less-discussed factor is radon gas, a naturally occurring radioactive gas that can accumulate in homes and buildings, especially in areas with high uranium content in the soil. While more commonly studied in Western countries, radon exposure is a possible risk factor in India too.

In some professions, occupational exposure to carcinogens like asbestos, silica, diesel exhaust, and arsenic can also increase the risk of lung cancer. This doesn’t just affect miners or construction workers—people working in old buildings, industrial plants, or near busy traffic zones are also at risk. The lack of stringent workplace safety standards in many developing countries only compounds this threat.

Genetics and second-hand smoke play roles too. Living with a smoker or being exposed to passive smoke in public or at home has a measurable impact. Additionally, certain genetic mutations (like EGFR mutations) are found more commonly in non-smoking Asian females with lung cancer—suggesting a distinct biological profile that deserves focused research.

So today, on World Lung Cancer Day, while we continue to advocate strongly against tobacco, let’s also broaden the conversation. Awareness campaigns, public health policies, and clinical strategies must account for these lesser-known but significant risk factors. We need cleaner air, safer workplaces, improved cooking technologies, and better diagnostics that don’t rely solely on smoking history.

Lung cancer is no longer just a smoker’s disease. And as we are learning, prevention must look far beyond the ashtray !