How air pollution is contributing to cancers in India

New Delhi: Increased exposure to carcinogens in the air is increasing the incidence of cancers of the lungs, bladder, breast, prostate, and blood, said health experts on National Cancer Awareness Day on Thursday.

National Cancer Awareness Day is observed on November 7 every year in India to raise awareness about the growing cancer burden in the country and inspire action towards prevention, early detection, and treatment.

India is home to over 1.4 billion people. Lifestyle changes, tobacco use, poor dietary habits, and inadequate physical activity are leading to a rapid surge in cancer cases.

About 800,000 new cancer cases are expected each year, with tobacco-related cancers accounting for as much as 35-50 per cent of all cancers in men and 17 per cent in women, According to estimates from the Health Ministry.

“Cancer rates are rising in India and have seen an upward trend in annual incidence rate. Currently, India records more than 14 lakh new cancer patients every year, and close to 9 lakh people die of it annually,” Dr. Abhishek Shankar, Assistant Professor, Department of Radiation Oncology, Dr BR Ambedkar Institute Rotary Cancer Hospital at AIIMS, Delhi, told IANS.

He attributed this rise to an increase in the "use of tobacco, alcohol, infections like HPV, Hepatitis virus and Helicobacter pylori, lifestyle changes, environmental factors, poor diets, and sedentary lifestyles".

While lifestyle factors play a major role, environmental changes -- particularly rising air pollution -- are also significant.

“India’s high levels of air pollution, especially PM2.5 exposure, are linked to rising lung cancer rates, including cases in non-smokers. Water and soil contamination from industrial pollutants increase risks for various cancers, impacting communities in industrial areas,” Shankar said.

The air quality in Delhi-NCR remained alarmingly poor on Thursday. As per the Central Pollution Control Board (CPCB), the average Air Quality Index (AQI) in the city was recorded at 362.

There is also substantial evidence from studies of humans and experimental animals as well as mechanistic evidence to support a causal link between outdoor (ambient) air pollution, especially PM 2.5 in outdoor air, with lung cancer and breast cancer incidence and mortality.

“It has a risk for other cancer types, such as bladder cancer, prostate cancer, leukaemia (blood cancer) but in limited numbers. Outdoor air pollution may also be associated with poorer cancer survival, although further research is needed,” Shankar said.

The World Health Organization (WHO) has classified outdoor air pollution as a Group 1 carcinogen, meaning there is sufficient evidence to conclude that it causes cancer in humans.

Air pollution in India is primarily caused by emissions from vehicles, industrial activities, and burning of biomass.

Dr Sajjan Rajpurohit, Senior Director - Medical Oncology, Max Super Speciality Hospital, told IANS that these pollutants contain carcinogenic substances such as benzene, formaldehyde, and polycyclic aromatic hydrocarbons (PAHs). Prolonged exposure to these substances can lead to cellular mutations and the development of cancer.

“Particulate Matter (PM2.5) is also one of the most harmful components of air pollution. The tiny particles can penetrate deep into the lungs and enter the bloodstream,” Rajpurohit said.

The health expert noted that children, the elderly, and individuals with pre-existing health conditions are particularly vulnerable to the effects of air pollution. Their increased susceptibility can lead to higher cancer rates in these groups, exacerbating the public health crisis.

Shankar called for a healthy lifestyle, including a balanced diet, regular exercise, and avoiding tobacco and alcohol along with reducing PM-2.5 exposure.

Dr. Sachin Trivedi, Director- Medical Oncology, HCG Cancer Center, also stressed the need for early detection for better treatment outcomes.

He called for “regular screenings for breast, lung, colorectal, and oral cancers to help effectively manage cancer”.