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Delhi’s recurring high AQI is a result of several factors, from vehicular emissions and industrial waste to seasonal crop-burning practices in neighboring states
The AQI in Delhi continued to remain in the ‘severe’ category.
As Delhi’s Air Quality Index (AQI) reaches hazardous levels, a toxic blanket of smog now envelops the city, creating immediate respiratory issues while posing severe long-term health risks for residents. With NASA satellite images capturing the scale of pollution, the issue has again brought into sharp focus the dangers of prolonged exposure to fine particulate matter (PM2.5), a major component of air pollution. While the adverse effects on daily respiratory health are well-documented, experts are increasingly concerned about the risk of chronic illnesses, including lung cancer, associated with ongoing exposure to these pollutants.
Delhi’s recurring high AQI is a result of several factors, from vehicular emissions and industrial waste to seasonal crop-burning practices in neighboring states. The toxic smog that results is dense with pollutants such as sulfur dioxide, nitrogen oxide, and most notably, PM2.5. PM2.5 particles are extremely small (2.5 micrometers or smaller in diameter), which enables them to be inhaled deeply into the respiratory system, infiltrating the lungs and potentially entering the bloodstream. Once inside the body, these particles cause not only acute respiratory conditions but also gradual damage that can lead to severe illnesses over time.
Dr. L.M. Darlong, Head of Thoracic Oncosurgery at the Rajiv Gandhi Cancer Institute and Research Centre (RGCIRC), explains the specific danger that PM2.5 poses: “Air pollution, particularly due to fine particulate matter known as PM2.5, is a significant risk factor for lung cancer. These tiny particles are small enough to be inhaled deeply into the lungs, where they can trigger mutations. Upon entering the bloodstream, PM2.5 particles may alter the DNA of lung cells, a process linked to the development of lung cancer. Lung cancer associated with PM2.5 exposure frequently involves mutations in genes like EGFR. This gene normally regulates cell growth and division, but when mutated or overly active, it can lead to uncontrolled cell growth and cancer. Long-term exposure to PM2.5—typically over a decade—raises the risk of developing lung cancer.”
The immediate effects of Delhi’s poor air quality are widely experienced by its residents, manifesting as respiratory issues such as cough, difficulty breathing, and throat irritation. Individuals with preexisting conditions, such as asthma and chronic obstructive pulmonary disease (COPD), are particularly vulnerable, as high pollution levels exacerbate their symptoms, sometimes leading to life-threatening episodes. The risk extends beyond immediate respiratory distress; it also contributes to cardiovascular issues, as PM2.5 particles in the bloodstream can induce inflammation and damage blood vessels, heightening the risk of heart disease and stroke.
Long-term exposure to polluted air compounds these health risks, particularly regarding chronic illnesses. The sustained inhalation of PM2.5 particles over years not only contributes to respiratory diseases but can also damage lung tissue to the point of triggering mutations. These mutations, as Dr. Darlong notes, involve the EGFR gene, which is typically responsible for regulating cell growth and division. Alterations in this gene can lead to uncontrolled cell proliferation, which significantly increases the risk of lung cancer. Studies have found that residents in high-pollution areas are more likely to experience genetic mutations linked to cancer, with PM2.5 exposure identified as a key contributor.
As Delhi and other urban areas continue to grapple with hazardous air quality, the need for both preventive measures and awareness campaigns becomes increasingly urgent. Policies to limit emissions, reduce industrial waste, and improve air quality monitoring are essential to mitigating the health risks of pollution. Personal measures, such as wearing high-efficiency masks, using air purifiers, and limiting outdoor exposure on high-AQI days, may provide some level of protection.
However, experts stress that individual actions are not enough to counteract the severe public health threat posed by air pollution. The escalating levels of pollutants like PM2.5 require a concerted effort from governments, industries, and communities alike to address air quality on a large scale. As Delhi’s air pollution crisis continues, the focus must shift from merely managing respiratory symptoms to actively working toward long-term solutions that can protect the health of its residents for generations to come.