Second-hand smoke puts 444 million Indians at risk, study finds

China, India and Indonesia accounted for nearly half of the world’s population exposed to second-hand smoke in 2023, with 664 million people exposed in China, 444 million in India and 142 million in Indonesia

5 min readUpdated: Sep 9, 2026 12:58 PM IST

Second-hand smoke is not simply a diluted version of the smoke inhaled by a smoker. (Source: Pexels)

At Dr Arvind Kumar’s Institute of Chest Surgery at Medanta Hospital in Gurugram, at least one in 10 lung cancer patients is now in their 30s. What worries the veteran chest surgeon even more is that about half of these younger patients are non-smokers. “Half of them are non-smokers,” says Dr Kumar, founder-trustee of the Lung Care Foundation.

His observation comes as a new study published in The Lancet Public Health estimates that 2.71 billion people worldwide, including 767 million children aged 0-14, were exposed to second-hand smoke in 2023. The findings are particularly concerning for India, where Dr Kumar says nearly half of lung cancer cases are now being diagnosed in non-smokers.

China, India and Indonesia together accounted for nearly half of the world’s population exposed to second-hand smoke in 2023. The study estimated that 664 million people were exposed in China, 444 million in India and 142 million in Indonesia.

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More than 3 lakh deaths in India

The health burden of second-hand smoke in India has also increased significantly. According to the study, deaths attributable to second-hand smoke in India have risen by nearly 50 per cent since 1990, reaching more than 3 lakh deaths in 2023.

Second-hand smoke was also responsible for more than 9 million disability-adjusted life years (DALYs) in India in 2023. DALYs measure the number of healthy years of life lost because of premature death or living with illness or disability.

Globally, ischaemic heart disease was the largest contributor to the health burden linked to second-hand smoke, accounting for about 12 million DALYs in 2023. The study examined nine health outcomes associated with second-hand smoke exposure, including cardiovascular disease, cancers, chronic obstructive pulmonary disease (COPD), lower respiratory infections, type 2 diabetes, otitis media and asthma.

The analysis, based on the Global Burden of Disease (GBD) 2023 study and published in The Lancet Public Health, examined second-hand smoke exposure and its health impact across 204 countries and territories between 1990 and 2023. The researchers describe it as the first dedicated GBD analysis focused specifically on second-hand smoke.

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There has been some progress: the proportion of people exposed to second-hand smoke globally fell by 22 per cent between 1990 and 2023. However, the estimated number of people exposed remained almost unchanged because of population growth. Exposure increased sharply in parts of sub-Saharan Africa and in North Africa and the Middle East.

Women and children face a heavier burden

The impact is not distributed equally. In Southeast Asia, East Asia and Oceania, women were 59 per cent more likely than men to be exposed to second-hand smoke, according to the analysis. Children are particularly vulnerable. Among children, lung infections were the leading cause of health loss linked to second-hand smoke. Across all age groups, however, heart disease accounted for the largest overall burden.

The researchers say the continued high number of people exposed to second-hand smoke, along with substantial differences between regions, highlights the need for stronger enforcement of tobacco-control measures.

Why second-hand smoke is harmful

Second-hand smoke is not simply a diluted version of the smoke inhaled by a smoker. It is a mixture of smoke from the burning end of a tobacco product and smoke exhaled by the smoker. People nearby can therefore inhale a complex mixture of toxic and cancer-causing chemicals even though they do not smoke themselves.

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These substances can cause oxidative stress and inflammation and can damage the lining of blood vessels. Over time, such exposure can increase the risk of cardiovascular and respiratory diseases as well as certain cancers.

Children are particularly susceptible because their lungs and immune systems are still developing. They also breathe more air relative to their body size than adults, potentially increasing their exposure to pollutants in the air.

The risk extends beyond lung cancer

Second-hand smoke is often discussed in the context of lung cancer, but its health effects are much broader. Long-term exposure has been linked to heart disease, stroke, respiratory illnesses and lung cancer. In children, exposure can increase the risk of lower respiratory infections and other breathing problems.

For non-smokers, particularly children and people with existing heart or respiratory conditions, the message from the latest analysis is clear: being a non-smoker does not mean being protected from the health effects of tobacco if smoke is present in the environment.

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The researchers’ findings also underline the importance of smoke-free homes, workplaces and public spaces, along with stronger implementation of tobacco-control measures. With billions of people still exposed globally, second-hand smoke remains a major—and largely preventable—public health risk.

Anuradha Mascarenhas

Anuradha Mascarenhas is a Senior Editor at The Indian Express, based in Pune. With a career spanning three decades, she is one of the most respected voices in Indian journalism regarding healthcare, science and environment and research developments. She also takes a keen interest in covering women's issues . Professional Background Education: A gold medalist in Communication and Journalism from Savitribai Phule Pune University and a Master’s degree in Literature. Author: She authored the biography At The Wheel Of Research, which chronicles the life and work of Dr. Soumya Swaminathan, the former Chief Scientist at the WHO. Key Focus: She combines scientific accuracy with storytelling, translating complex medical research into compelling public and human-interest narratives. Awards and Recognition Anuradha has won several awards including the Press Council of India's national award for excellence in journalism under the gender based reporting category in 2019 and the Laadli Media award (gender sensitivity -2024). A recipient of the Lokmat journalism award (gender category-2022), she was also shortlisted for the RedInk awards for excellence in journalism-2021. Her debut book At The Wheel Of Research, an exclusive biography of Dr Soumya Swaminathan the inaugural chief scientist of World Health Organisation was also nominated in the Popular Choice Category of JK Paper AUTHER awards. She has also secured competitive fellowships including the Laadli Media Fellowship (2022), the Survivors Against TB – New Research in TB Media Fellowship (2023) and is part of the prestigious 2025 India Cohort of the WomenLift Health Leadership Journey.” Recent Notable Articles (Late 2025) 1. Cancer & Specialized Medical Care "Tata Memorial finds way to kill drug-resistant cancer cells" (Nov 26, 2025): Reporting on a breakthrough for triple-negative breast cancer, one of the most aggressive forms of the disease. Discipline, diet and purpose; How a 97-year-old professor defies ageing'' (Nov 15, 2025) Report about Prof Gururaj Mutalik, the first Head of Department at Pune's B J Government Medical College who at 97 credits his longevity to healthy habits and a strong sense of purpose. 2. Environmental Health (The "Breathless Pune" Series) Long-term exposure even to 'moderate' air leads to chronic heart, lung, kidney issues" (Nov 26, 2025): Part of an investigative series highlighting that even "safe" pollution levels are damaging to vital organs. "For every 10 µg/m3 increase in PM2.5 level, there was 6-8% jump in medicine sales" (Nov 23, 2025): Using commercial data to prove the direct link between air quality and respiratory illnesses in Pune. 3. Lifestyle & Wellness News "They didn't let cancer, diabetes and heart disease stop them from travelling" (Dec 22, 2025): A collaborative piece featuring survivors who share practical tips for traveling with chronic conditions. At 17, his BP shot up to 200/120 mmHG; Lancet study flags why child and teen hypertension doubled between 2000 and 2020'' (Nov 12,2025)--A report that focusses on 17-year-old-boy's hypertensive crisis and reflects the rising global trend of high blood pressure among children and adolescents. 4. Scientific Recognition & Infrastructure For promoting sci-comm, gender diversity: IUCAA woman prof highlighted in Nature" (Nov 25, 2025): Covering the global recognition of Indian women scientists in gender studies and physics. Pune researchers find a spiral galaxy like the Milky Way from early universe'' (December 3, 2025)- A report on how Indian researchers discovered a massive galaxy that existed when the universe was just 1.5 billion years old , one of the earliest to have been observed so far. Signature Beat: Health, Science & Women in Leadership Anuradha is known for her COVID-19 reportage, where she was one of the first journalists to provide detailed insights into the Covishield and Covaxin trials. She has a dedicated interest in gender diversity in health and science, often profiling women researchers who are breaking the "leaky pipeline" in STEM fields. Her writing style is scrupulous, often featuring interviews with top-tier scientists and health experts from various institutions. ... Read More

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