As Diwali celebrations commence in South Asia, particularly in northern India, a familiar and dangerous foe has returned: hazardous winter air. This annual resurgence of smog, exacerbated by seasonal weather patterns, is prompting concerns about how residents can safely observe the holiday.
Winter air quality challenges are not unique to India. Pakistan and China also contend with severe smog during this season, where trapped cold air prevents pollution from dispersing. In Eastern Europe, the burning of coal and wood for heating contributes significantly to winter pollution. Meanwhile, Western Hemisphere nations grapple with air quality issues, often stemming from smoke generated by summer wildfires that drift across the United States and Canada.
For the estimated 1 billion people worldwide who celebrate Diwali, a significant Hindu and Jain festival, the tradition of setting off fireworks adds a potent burst of pollution to an already critical problem. Beyond fireworks, daily life in India, Pakistan, and other parts of South Asia contributes to air pollution through traffic, industrial emissions, construction dust, and the burning of agricultural residue and waste. Weak winds and stagnant winter air trap these pollutants close to the ground, creating a dangerous buildup.
Experts emphasize that regardless of location or the time of year, simple precautions can help mitigate exposure to harmful pollutants. Checking the Air Quality Index (AQI), wearing well-fitting masks, and utilizing air purifiers are among the recommended measures.
In India, the AQI translates pollution levels into health warnings, with readings between 201–300 classified as "poor," 301–400 as "very poor," and 401–500 as "severe." At severe levels, even healthy individuals can experience adverse health effects. Before venturing outdoors, individuals are advised to consult government or private websites for pollution data from nearby monitoring stations, paying attention to the time of the last update, as citywide averages can mask localized pockets of extreme pollution.
Delhi, a city of over 20 million, frequently experiences severe air quality. Last year, fine particle pollution in the capital averaged about 19 times the World Health Organization’s annual guideline. Air pollution monitors in the city have repeatedly reached their maximum displayable readings in recent years. In response, city authorities have implemented temporary restrictions on construction, industry, and vehicles, though public health experts note these measures often fall short of addressing root causes. The city is also pursuing a long-term strategy to encourage the adoption of electric vehicles.
Dr. Arvind Kumar, a chest surgeon and founder trustee of the Lung Care Foundation, recommends using properly fitted N95 or N99 masks when outdoors during periods of heavy pollution. These masks, available through various retailers, are designed to filter out a significant percentage of airborne particles. It is crucial to ensure a proper seal around the nose, mouth, and chin, as facial hair can compromise effectiveness. Disposable masks should be replaced when dirty, damaged, or difficult to breathe through. Importantly, masks are not suitable for children under two years old, and individuals with pre-existing heart or lung conditions should consult a doctor regarding their use. Loose surgical masks, cloth masks, and scarves offer minimal protection against fine particles.
Pollution can lead to persistent coughing, airway inflammation, asthma-like symptoms, and increase the risk of pneumonia, heart attacks, and strokes. Prolonged exposure has also been linked to impaired lung development in children and lung cancer. During periods of high pollution, strenuous outdoor exercise, especially in the early mornings when pollution levels can be elevated, should be avoided.
Indoors, the use of air purifiers equipped with High-Efficiency Particulate Air (HEPA) filters can help reduce exposure. The effectiveness of a purifier depends on its capacity for the room size and its Clean Air Delivery Rate (CADR). Purifiers should be placed in frequently occupied areas like bedrooms, kept running consistently, and their airflow should be unobstructed. While HEPA filters capture particles, substantial activated-carbon filters can address some gases. No purifier can eliminate all pollutants, and devices that intentionally produce ozone should be avoided as it irritates the lungs.
Reducing indoor air pollution also involves avoiding incense, mosquito coils, and candles, which can release particles that linger. Similarly, fireworks pollution can persist overnight. Electric lights offer a celebratory alternative to firecrackers. India’s health ministry also advises reducing smoky cooking, using kitchen exhausts that vent outdoors, and damp-mopping floors and surfaces to avoid stirring up settled particles.
Public health experts acknowledge that personal precautions have limitations. Individuals working outdoors or those who cannot afford air purifiers face greater risks. They advocate for sustained action to address the sources of pollution and for accessible healthcare for those already affected, emphasizing that lasting protection requires governmental efforts to improve air quality.