Air Pollution Leads to Lung Cancers

Hyderabad: The recently released Population-Based Cancer Registry for Hyderabad highlights a rise in tobacco-related cancers, including lung, mouth, and tongue cancers. However, doctors in the city are also noticing an increase in lung cancer cases among non-smokers, with air pollution emerging as a significant contributing factor.

Lung cancer is increasingly being diagnosed in individuals who have never smoked. "Around 30 per cent of lung cancer cases are among non-smokers," said Dr Sadashivudu Gundeti, head of the medical oncology department at the Nizam's Institute of Medical Sciences (NIMS). A key cause of this rise is second-hand smoke, such as exposure from a spouse who smokes or sitting in a pub where others are smoking in urban areas and the use of firewood in rural areas.

Air pollution is another major factor. A recent study by the International Agency for Research on Cancer (IARC) found an increase in adenocarcinoma, a subtype of lung cancer typically seen in non-smokers. The study noted a spike in such cases in Southeast Asia, particularly in China, and suggested that air pollution might play a significant role in exacerbating adenocarcinoma.

In India, studies have shown a growing number of lung cancer cases among never-smokers. "Several studies indicate that between 40 per cent and 50 per cent of lung cancer cases in Southeast Asia involve non-smokers, with the figure rising to 83 per cent among South Asian women. Important risk factors for lung cancer in non-smokers include air pollution — especially particulate matter (PM2.5)—which is a major concern in urban areas," explained a study conducted by doctors at Tata Memorial Hospital, Mumbai, and others, recently published in The Lancet.

Dr Sainath, a medical oncologist, noted, "While it is difficult to pinpoint specific pollutants or air quality levels that directly cause cancer, exposure to air pollution is certainly a risk factor. Prolonged exposure can create an environment where cancer is more likely to develop. Even a smoker who quits may develop cancer 20 years later, but continuous exposure to polluted air can increase the risk as well."

In Hyderabad, air pollution levels have been steadily rising, increasing the risk for lung cancers. According to the National Clean Air Programme (NCAP), the city is among the top three areas in Telangana where pollution control goals — bringing AQI levels below 60 — have not been met, earning it the label of a "Non-Attainment City." Other areas facing similar challenges include Patancheru, Sangareddy, Nalgonda, and soon Warangal. "The rise in population, vehicles, and construction activities are major contributors to the increasing air pollution in Hyderabad. While Nalgonda's AQI levels have dropped to around 60, Hyderabad's AQI remains at 83," noted an official from the Telangana Pollution Control Board.