Karmactive StaffMany morning walkers in Lodhi Garden now wear N95 masks year-round, not just during winter anymore, while others continue their routines despite the pollution. School buses crawl through a gray haze that wraps around buildings like a suffocating blanket. This is Delhi’s new normal – where breathing itself has become a health hazard. And the latest data confirms what doctors have been warning about: you don’t have to light a cigarette to develop lung cancer in India’s capital anymore.
The numbers tell a story that’s hard to ignore. Non-smokers comprised 40.9% of the study sample at a major North Indian cancer center, according to research published in 2022. Even more alarming, 50 per cent patients were found to be non-smokers in a Sir Ganga Ram Hospital study that examined 150 lung cancer cases between 2012 and 2018.
The Air That Kills
Picture this: Delhi’s air quality regularly hits PM2.5 levels that are 8–10× safe AQI limits. To put that in perspective, breathing Delhi’s air during peak pollution days has been compared to smoking 12-13 cigarettes daily, according to research from Berkeley Earth that equates 22 μg/m³ of PM2.5 to one cigarette. The fine particulate matter, smaller than 1/30th the width of a human hair, penetrates deep into lung tissue, triggering cellular changes that can lead to cancer.
Dr. Arvind Kumar, Chairman of the Centre for Chest Surgery at Sir Ganga Ram Hospital, has observed this transformation firsthand. He has noted that when he started operating on cancer patients in the late 1980s, patients’ lungs showed less carbon pigmentation compared to now, when the lungs of many patients have increased carbon deposits visible on resected specimens.
The shift has been dramatic. According to Dr. Kumar’s observations, historically, lung cancer patients were predominantly smokers, but a study conducted at Sir Ganga Ram Hospital between 2012 and 2018 found that 50% of lung cancer patients were non-smokers. Dr. Kumar has noted the unprecedented change in the ratio of smokers to non-smokers suffering from lung cancer.
Young Lives at Risk
Perhaps most troubling is who’s getting sick. A study of 150 lung cancer cases at Sir Ganga Ram Hospital between 2012 and 2018 found that over 21 per cent of patients were below the age of 50. Among non-smokers in the younger age category (less than 50 years old), the proportion rose to 70 percent, and the study noted that none of the patients under 30 had ever smoked.
While individual case examples highlight the human impact of this trend, the statistical patterns tell a more significant story. Young non-smokers with no history of occupational exposure increasingly find themselves diagnosed with lung cancer after experiencing persistent respiratory symptoms.
The Numbers Keep Rising
Delhi’s cancer registry paints a grim picture of steady increase. Male lung cancer rates climbed from 8.4% to 10.6% between 1988 and 2015, while female rates nearly doubled from 1.9% to 3.4%. “The ratio of non-smokers among those suffering from lung cancer is increasing year after year,” notes Dr. Anant Mohan, head of pulmonology at AIIMS.
The trend extends beyond Delhi. Studies from various cancer centers across India show an increasing percentage of lung cancer patients with no history of smoking.
The study predicts a significant increase in lung cancer cases in India by 2025 compared to previous years. The rate of lung cancer has surged from 6.62 per 1,00,000 in 1990 to 7.7 per 1,00,000 in 2019 and a significant rise is expected in urban areas by 2025.
Why Non-Smokers? The Science Behind It
The culprit isn’t just outdoor pollution. Multiple factors converge to create this perfect storm:
PM2.5 and PM10 particles: Delhi’s air carries microscopic particles that lodge deep in lung tissue. According to CPCB source apportionment studies, about 80-85% of Delhi’s SO2 emissions come from industrial sources, while vehicles contribute 25-30% of PM2.5 and around 35% of NOx emissions. Ongoing construction and road dust are major PM sources—contributing around 40% of PM2.5 and 55-60% of PM10 pollution.
Indoor pollution: Women cooking with biomass fuels face significant exposure. Studies from South India have found high percentages of female lung cancer patients who are never-smokers with a history of biomass fuel exposure.
Genetic mutations: Asian populations show higher rates of EGFR (Epidermal Growth Factor Receptor) mutations. Research from North India found EGFR mutation and ALK rearrangement rates in the cohort were 23.3% and 10.1%, respectively, and were more frequent in non-smoking patients.
Occupational hazards: Factory workers, miners, and those who are exposed to diesel exhaust, silica dust, arsenic, chromium, nickel, cadmium, coal tars or chemical fumes have an increases risk, explains Dr. Pushpinder Gulia from CK Birla Hospital, Gurugram.
Radon exposure: Inhaled radon gas decays into radioactive particles that can damage lung tissue over time, leading to cancer. This can be found in homes and poorly ventilated buildings built over radon-rich soil.
More Posts
A Different Disease Pattern
Non-smoker lung cancer behaves differently. Non-smokers were more likely than smokers to experience disease onset at a younger age (P = 0.004) and metastasis (P < 0.001). They typically develop adenocarcinoma (77.4% of cases) rather than the squamous cell type common in smokers.
The silver lining? Research studies suggest non-smokers may respond better to treatment than smokers, particularly those with certain genetic mutations who may benefit from targeted therapies.
Diagnosis Challenges
Early detection remains challenging. Studies show that around 10 percent of lung cancer patients are diagnosed incidentally while about 30 percent are initially misdiagnosed. Many cases get mistaken for tuberculosis, delaying proper treatment. “Symptoms like chronic cough, chest pain, and weight loss are common to both TB and lung cancer. In TB-prevalent regions like India, early-stage lung cancer is often misdiagnosed as TB,” notes Dr. Vinod K Ramani from Sammprada Hospital, Bengaluru.
Medical professionals report seeing increasing cases of lung cancer in patients with no traditional risk factors. In many cases, these are detected during routine imaging after prolonged respiratory symptoms. Many cases involve non-smokers developing lung cancer despite leading what would traditionally be considered healthy lifestyles.
The National Health Crisis
The broader impact on India’s health is staggering. Air pollution in India is estimated to cause 670,000 deaths annually and particularly aggravates respiratory and cardiovascular conditions including chronic bronchitis, lung cancer and asthma. More recent estimates are even more alarming: 1·67 million (95% uncertainty interval 1·42–1·92) deaths were attributable to air pollution in India in 2019, accounting for 17·8% (15·8–19·5) of the total deaths in the country.
The economic burden is equally severe. The economic loss due to lost output from premature deaths attributable to air pollution in India in 2019 was US$28·8 billion (95% UI 21·4–37·4), and from morbidity attributable to air pollution was $8·0 billion.
The APAC Consensus Sounds the Alarm
The Asia Pacific Lung Cancer Policy Consensus, released in July 2025, demands urgent action. Their recommendations include:
- Broadening risk definitions beyond smoking
- Strengthening air quality regulations
- Expanding screening access for high-risk non-smokers
- Developing region-specific treatment protocols
Cities including Delhi and Lucknow report high levels of PM2.5 particulate pollution. This exposure correlates with elevated lung cancer rates even in individuals who never smoked. The consensus emphasizes that Delhi’s air has become a public health emergency requiring immediate intervention.
What Can Be Done?
For individuals living in Delhi and other polluted cities, doctors recommend:
- Using air purifiers at home, especially in bedrooms
- Wearing N95 masks during high pollution days
- Getting regular health check-ups if experiencing persistent cough or breathing issues
- Avoid peak pollution hours (6–10 AM, 5–9 PM)
Dr. Shyam Aggarwal, senior consultant, Pulmonology, SGRH, underlined that low-dose CT could be a vital tool for early detection of lung cancer. Regular screening is recommended for high-risk individuals.
The Road Ahead
India faces a dual challenge of environmental reform and healthcare preparedness. Crop burning in nearby states contributes significantly to pollution levels in winter, accounting for about 30-35% of Delhi’s pollution during peak season. Without immediate action on air quality, lung cancer rates will only climb higher.
The transformation of lung cancer from a smoker’s disease to an environmental one demands a complete rethink of prevention strategies. Dr. Arvind Kumar has expressed concerns about the impact of air pollution on health, noting that in Delhi, newborns are exposed to harmful pollutants from their first breath.
Dr. Vishal Rao, head and neck surgical oncologist at HCG Bengaluru, has observed an increasing percentage of lung cancer cases occurring in non-smokers. He observes that air pollution is rapidly emerging as a leading concern, particularly in urban metropolitan areas.
Urban India stands at a crossroads. The choice is clear: clean up the air or watch lung cancer rates soar among those who never touched a cigarette. For the morning walkers in Lodhi Garden, the school children in their buses, and the millions who call Delhi home, breathing clean air shouldn’t be a luxury – it should be a basic right.
The data speaks volumes. The medical community has raised the alarm. The APAC Consensus has laid out the roadmap. What remains is the political will to prioritize public health over short-term economic gains. Because in Delhi today, simply breathing has become a calculated risk.
Protecting Yourself Indoors
While most of the focus remains on outdoor air pollution, experts warn that indoor air quality can sometimes be worse than outdoor conditions. Household products, building materials, and even common items like mosquito coils can release harmful compounds that accumulate in poorly ventilated spaces. For comprehensive protection, consider both outdoor and indoor pollution sources when developing personal health strategies.
