The national capital continues to grapple with an alarming air quality crisis, with pollution levels worsening steadily over the past week. On Sunday, November 2, 2025, Delhi’s overall Air Quality Index (AQI) plunged further into the ‘very poor’ category, with certain areas recording readings that crossed into the ‘severe’ zone. According to data from the Central Pollution Control Board (CPCB), the overall AQI at 7 a.m. on Sunday was 377. By 10 a.m., neighborhoods such as Anand Vihar, Chandni Chowk, Nehru Nagar, RK Puram, Rohini, and several others reported AQI readings exceeding 400, indicating a hazardous level of air pollution that poses immediate health risks to residents.

The persistent deterioration of air quality has prompted renewed concern among public health experts and medical professionals, particularly those specializing in pulmonary and cardiovascular health. Former AIIMS doctor and senior pulmonologist Dr. Gopi Chand Khilnani, who currently serves as chairman of the PSRI Institute of Pulmonary Medicine, has issued strong advisories for vulnerable populations. In an interview with the Indian Express, Dr. Khilnani emphasized that while not everyone can leave Delhi, individuals with chronic lung or heart conditions, patients on oxygen support, and those with the means to relocate should consider temporarily moving to less polluted environments to avoid severe health complications.

“Everybody cannot afford to leave Delhi, because it is not simple,” Dr. Khilnani acknowledged. “But for those who have chronic lung disease or chronic heart disease, those on oxygen, and those who have the opportunity and ability to go abroad or to less polluted places, I very safely advise them to leave Delhi for six to eight weeks from now. This is to protect themselves from distressing breathlessness, oxygen dependence, and other complications that arise from prolonged exposure to extremely poor air quality.”

Delhi’s air pollution crisis, which is particularly acute during the winter months, has far-reaching health consequences. Dr. Khilnani highlighted that air pollution is no longer only a concern for respiratory conditions; it has systemic effects on multiple organs and can significantly exacerbate pre-existing medical conditions. According to studies conducted at AIIMS, exposure to high levels of air pollutants can stunt lung growth in children, leaving them more susceptible to respiratory illnesses later in life. Moreover, while tobacco use and smoking were previously the predominant causes of chronic obstructive pulmonary disease (COPD) and lung cancer, environmental pollution has now emerged as a major contributor. Dr. Khilnani explained, “Three or four decades ago, tobacco or smoking accounted for 90% of COPD cases. Today, about 50% of these cases are caused by indoor and outdoor air pollution. Similarly, over 80% of lung cancer cases were earlier attributed to tobacco smoking. Today, 40% of lung cancer patients have never smoked, and we are seeing an increase in cases among younger individuals.”

Beyond respiratory health, prolonged exposure to severe air pollution can affect the cardiovascular system, the brain, kidneys, intestines, the endocrine system, and overall immunity. Dr. Khilnani stressed that vulnerable populations—particularly children, the elderly, and those with pre-existing conditions—face heightened risks. “Air pollution doesn’t just make breathing difficult,” he said. “It can exacerbate heart conditions, lead to neurological issues, affect kidney function, disrupt endocrine balance, and suppress the immune system, making individuals more prone to infections and chronic illnesses.”

Given the severity of the situation, many residents turn to air purifiers as a protective measure. Dr. Khilnani addressed the utility of air purifiers in mitigating exposure to indoor pollutants. According to him, a high-quality air purifier can help reduce particulate matter in the room, but its effectiveness depends on specific usage practices. “A good quality air purifier can cover the volume of a room and make the air cleaner. However, it must be running continuously and positioned close to the person using it,” he explained. “The room should remain closed for most of the time. Frequent opening of doors or windows reduces its efficiency, as outdoor pollutants enter the indoor space and compromise air quality.”

While the World Health Organization (WHO) does not universally endorse air purifiers as a method to improve overall health, Dr. Khilnani noted that they are particularly useful for individuals with chronic respiratory diseases, COPD, or heart conditions who spend extended periods indoors. “Air purifiers are not a substitute for broader environmental action or medical intervention, but for those at high risk, they provide a degree of protection against exposure when staying indoors is the primary option,” he added.

In addition to air purifiers, Dr. Khilnani stressed the importance of broader preventive measures to minimize exposure to polluted air. He recommended the use of N95 or similar high-efficiency masks when going outdoors, avoiding outdoor physical activity during peak pollution hours, maintaining a diet rich in antioxidants to support lung health, and monitoring air quality reports regularly to plan daily routines. Vulnerable groups should limit travel and ensure that indoor spaces are well-ventilated but protected from infiltration of outdoor air.

Experts like Dr. Khilnani also caution against complacency regarding the long-term effects of air pollution. Unlike acute illnesses caused by infections, the consequences of prolonged exposure to polluted air accumulate gradually, often manifesting in chronic diseases that can impair quality of life over decades. Children growing up in highly polluted areas may develop reduced lung capacity, adults may experience increased cardiovascular events, and older adults may face worsening of existing chronic conditions. “We often think that once the immediate smog clears, the danger is over. But the damage is cumulative, and exposure over months or years can have lasting consequences,” Dr. Khilnani said.

Delhi’s air pollution problem is exacerbated by a combination of factors including vehicular emissions, industrial activity, construction dust, seasonal crop burning in neighboring states, and meteorological conditions that trap pollutants close to the ground. During winter, the drop in temperature, low wind speeds, and thermal inversion contribute to the persistence of smog, making air quality management particularly challenging. City authorities have attempted to implement measures such as odd-even vehicle schemes, restrictions on construction activity, and promotion of cleaner fuel, but the efficacy of these measures is often limited by enforcement gaps and regional pollution sources beyond Delhi’s direct control.

The current situation, with AQI readings consistently in the ‘very poor’ to ‘severe’ range, serves as a reminder of the urgent need for both individual-level precautions and long-term policy interventions. Experts argue for stronger regulatory measures, regional cooperation to prevent crop burning, investment in public transportation to reduce vehicular emissions, and promotion of clean energy solutions. Public awareness campaigns, real-time air quality monitoring, and proactive advisories to at-risk populations are also crucial components of an effective pollution management strategy.

For residents who cannot leave Delhi due to professional or personal obligations, Dr. Khilnani recommends creating safe indoor environments using air purifiers, maintaining minimal outdoor exposure, and following health precautions such as wearing masks and avoiding strenuous outdoor activities. “Everyone cannot leave Delhi, but those who can, particularly individuals with chronic health issues, should seriously consider it for the next six to eight weeks. For others, using protective measures indoors and minimizing exposure is essential,” he emphasized.

In conclusion, Delhi’s ongoing air pollution crisis, which has seen the AQI reach hazardous levels in multiple areas, poses a serious public health challenge. While the situation may appear temporary due to seasonal factors, its effects are long-lasting and can severely impact vulnerable populations. Dr. Gopi Chand Khilnani’s advice underscores the gravity of the situation and the need for both immediate personal precautions and broader systemic interventions. Residents are urged to monitor air quality regularly, adopt protective measures indoors and outdoors, and seek medical attention promptly if they experience respiratory or cardiovascular distress. The combination of individual vigilance and policy action is essential to mitigate the impact of extreme air pollution in India’s national capital.