As India grapples with severe air pollution, particularly in cities such as Delhi, a recent study sheds light on a lesser-known health risk: an increase in head and neck cancers linked to pollution exposure.
The research, conducted by a team from Wayne State University, Johns Hopkins University, and Mass General Brigham, has found a correlation between particulate matter pollutants (PM2.5) and higher rates of head and neck aerodigestive cancers. Published in Scientific Reports journal, the study suggests that the effects of pollution may extend beyond respiratory illnesses.
The study, titled “Air Pollution Exposure and Head and Neck Cancer Incidence”, was led by John Cramer and John Peleman, from Wayne State University School of Medicine. Traditionally, air pollution research has focussed on lung diseases. This study, however, explores the cancer risks that pollution may pose to the upper airway, specifically head and neck cancers. Cramer explained that exposure to pollutants could impact the head and neck’s lining in a manner similar to smoking, a known risk factor for these cancers.
The team analysed data from the US Surveillance Epidemiology and End Results (SEER) national cancer database, covering 2002 to 2012, and observed that head and neck cancer rates rose in regions with high PM2.5 pollution after a five-year lag.
These findings are particularly relevant for India, where PM2.5 levels are frequently elevated due to industrial emissions, vehicle exhaust, and seasonal agricultural burning. The researchers also pointed to the need for improved air quality standards.
“Our study indicates the importance of addressing air pollution to reduce cancer risks,” said co-author Amanda Dilger, of Massachusetts Eye and Ear.
As pollution levels spike annually, particularly in winter, experts suggest that addressing air quality could help mitigate pollution-related health risks, including the potential development of cancers related to airborne toxins.
“Air pollution is a significant cause of cancer, particularly affecting the upper respiratory tract, which includes the pathway air follows as we breathe—from the nose to the pharynx, glottis (voice box), trachea, and finally to the lungs. Polluted air often contains harmful particles, measured by the Air Quality Index (AQI). Larger particles, especially those with high levels of pollutants like carbon compounds (e.g., benzene) and harmful gases (e.g., methane, sulphur compounds), pose a serious risk. Additionally, heavy metals like lead are frequently present in polluted air,” said Dr Mandeep Singh Malhotra, Director of Surgical Oncology, CK Birla Hospital, Delhi.
“As these pollutants travel through the respiratory tract, they can damage the lining or deposit in the cells of areas like the nasal cavity, nasopharynx, larynx, and trachea. While the body typically has mechanisms to repair such damage, repeated exposure may overwhelm these defences, leading to mutations in affected cells. Over time, these mutations can result in cancers of the nasopharynx, pharynx, larynx, and trachea,” he said, adding, that some air is also inhaled through the mouth, increasing the risk of oral cancers, including cancers of the tongue and tonsils. Thus, prolonged exposure to air pollution significantly raises the risk of cancers along the upper respiratory tract, he said.
As air quality levels continued to decline across several states and Union Territories, the Union Health Ministry issued an advisory in early October, ahead of Diwali, urging immediate action to address the health risks posed by rising pollution. In recent weeks, the Air Quality Index (AQI) has reached “moderate to poor” levels in numerous regions, with experts warning that air quality may deteriorate further as the winter season sets in and festivities begin.
The government further advised citizens to take personal precautions, such as monitoring AQI levels using government apps before going outdoors, avoiding congested areas, and opting for cleaner cooking and heating methods. Vulnerable populations, including the elderly and those with respiratory or cardiovascular conditions, should limit outdoor activities when air quality is poor, the health ministry said.
In cases where individuals experience severe symptoms, the Ministry urged them to seek immediate medical attention. The advisory was sent to principal secretaries of all States and Union Territories, as well as health officials under the National Health Mission and the National Programme on Climate Change and Human Health.