Each year, the days following Diwali bring a familiar haze across many Indian cities. In Delhi and other parts of North India, the Air Quality Index (AQI) often touches the “severe” mark as the smoke from firecrackers, vehicle emissions, and stagnant winter air combine to form a toxic mix. While most people stay indoors, assuming they’re safe, fine particulate matter easily seeps inside homes, turning indoor spaces into hidden pollution traps.
Here’s a clear, science-backed guide on how to keep your AQI down inside your home post-Diwali and protect your family’s health.
Air pollution levels spike dramatically after the festival. Data from the Central Pollution Control Board (CPCB) shows AQI readings frequently exceeding 400 in parts of Delhi after Diwali night — a level considered “severe.”
Reports by The Times of India and Hindustan Times highlight that fine particles such as PM2.5 and PM10 can stay suspended in the air for hours and travel indoors through even the smallest openings.[1,2]
These particles settle deep in the lungs and bloodstream, causing irritation, coughing, and difficulty in breathing. Those with asthma or heart disease may experience worsening symptoms even at short-term exposure.
People spend most of their day inside — at home, in offices, or in vehicles — so indoor air quality (IAQ) has a direct impact on overall health. Studies show that long-term exposure to particulate matter can trigger inflammation and oxidative stress, leading to respiratory and heart problems.[3]
Experts at Cleveland Clinic explain that poor indoor air also raises the risk of allergies and cardiovascular strain.[4] Harvard Health notes that high levels of carbon dioxide and volatile organic compounds (VOCs) indoors can reduce alertness and focus.[5]
Though the evidence on cognitive effects is still emerging, the impact on lung and heart health is well-established.
Children, older adults, and people with asthma, COPD, or heart disease are most vulnerable to post-Diwali pollution. Their immune and respiratory systems are more sensitive to fine particles and chemical irritants. For them, clean indoor air is not just comfort—it’s essential prevention.
India's National Centre for Disease Control (NCDC) and the World Health Organization (WHO) recommend measures to reduce exposure during periods of poor air quality. The following steps can help limit indoor exposure to particulate pollution. 7,8
On days when AQI exceeds 200, India's NCDC advises avoiding opening external doors and windows during morning and late-evening hours. It recommends ventilating rooms when necessary between 12 pm and 4 pm. However, outdoor air quality can vary by location and day, so check local pollution levels before opening windows. Keep doors and windows closed when outdoor pollution is high to limit the entry of polluted air. 7
Portable air filters can reduce indoor PM2.5 concentrations by approximately 40–82%, according to the real-world studies examined in a WHO evidence review. However, the reduction varies depending on the filtration system, room conditions, outdoor pollution infiltration and indoor activities. These figures should not be considered a guaranteed outcome for every household. 8
These remove indoor pollutants from cooking fumes, humidity, and cleaning agents.
Whenever possible, use kitchen exhaust hoods that vent directly outdoors rather than simply recirculating indoor air.
Wipe surfaces and floors using wet mops or microfiber cloths. Avoid dry dusting, which redistributes fine particles into the air.
Use a damp microfiber cloth to clean furniture, window sills and other surfaces where dust and particulate matter may accumulate. India's NCDC also recommends wet mopping instead of sweeping to reduce exposure to air pollution. 7
Refrain from smoking, burning candles, or lighting incense sticks inside the house as they emit harmful particles and gases.
Also avoid vaping, burning wood or other solid fuels indoors, and using aerosol sprays unnecessarily during periods of poor outdoor air quality. 9
Cooking, particularly frying, grilling, baking and burning food, can increase indoor particulate matter levels. Use a kitchen exhaust hood that vents outdoors whenever possible. Keep it running while cooking and for 10–20 minutes afterwards. Cooking on the back burners, when possible, can also improve the capture of cooking emissions. If an outdoor-vented hood is unavailable, use an exhaust fan and ventilate when outdoor air quality permits. 10
Choose an air purifier with a genuine HEPA filter and a Clean Air Delivery Rate (CADR) suitable for the room size. Check the manufacturer's recommended room coverage before purchasing a device.
Place the purifier in a room where family members spend considerable time, such as a bedroom or living area. Running it for longer periods and at higher fan speeds generally increases the amount of air filtered. Clean or replace filters according to the manufacturer's instructions. 9
HEPA filters capture airborne particles, including PM2.5, but do not automatically remove gases and all VOCs. Air purifiers with activated carbon filters may help remove certain gaseous pollutants, depending on the amount and design of the filter. 9
Avoid ozone generators and air-cleaning devices that intentionally release ozone. Ozone can irritate the respiratory tract, damage the lungs and worsen respiratory conditions such as asthma. 11
See also: Best Air Purifier Features for Allergies - HEPA, CADR Explained
During periods of severe outdoor pollution, designate one room where family members can spend most of their time. Choose a room that can be kept relatively closed off from outdoor air and operate a correctly sized air purifier in it. Avoid activities that generate indoor particles, such as smoking, burning incense or candles, and frying food in this space. This approach may help reduce exposure, particularly for children, older adults and people with existing respiratory or cardiovascular conditions. 12
Check local outdoor AQI updates through CPCB's monitoring portal or other reliable air-quality services before deciding when to ventilate. Indoor air-quality monitors can provide additional information about household PM2.5 levels, but their accuracy and measurement limitations should be considered. 7,13
Although some studies have examined the ability of houseplants to absorb VOCs, research indicates that ordinary potted plants are not effective substitutes for mechanical air filtration in typical indoor environments. A 2020 review found that an impractically large number of plants would be needed to achieve meaningful VOC removal in buildings. This research examined VOC removal, not specifically PM2.5 filtration. 14
See also: Can Houseplants Really Purify the Air in Your Home? What the Science Actually Says
Seek medical advice if coughing, wheezing, eye irritation or breathing discomfort persists or worsens. Breathlessness, chest pain or discomfort, dizziness and significant difficulty breathing warrant prompt medical evaluation. India's NCDC advisory specifically identifies breathlessness, cough, chest discomfort or pain, giddiness and eye irritation as symptoms requiring medical attention. 7
The WHO notes that although properly fitted respirators such as N95 can filter particulate matter, evidence of health benefits from their use by the general population in real-world air-pollution conditions is limited. Routine respirator use is therefore not recommended as a general public-health measure. Their use may be considered in specific, short-term situations under appropriate guidance. People with existing respiratory or cardiovascular conditions should seek medical advice before using respirators. 8
Post-Diwali smog is an annual challenge, but it’s possible to protect your indoor environment with consistent effort. Understanding how to keep your AQI down inside your home post-Diwali, through smart ventilation, filtration, and healthy habits, can significantly cut your exposure to harmful air pollutants. Cleaner air at home is not a luxury; it’s an important part of preventive healthcare, especially in the weeks following Diwali.
“Delhi’s Air Pollution Surges to Hazardous Levels Post-Diwali.” The Times of India.
“As AQI Rises Post-Diwali, Experts Share How to Protect Lungs, Eyes, and Home.” Hindustan Times.
Vardoulakis, Sotiris, Evangelia Giagloglou, Stefan Steinle, A. Davis, S. Sleeuwenhoek, K. S. Galea, K. Dixon, and J. O. Crawford. “Indoor Exposure to Selected Air Pollutants in the Home Environment: A Systematic Review.” International Journal of Environmental Research and Public Health 17, no. 23 (2020): 8972. https://doi.org/10.3390/ijerph17238972.
Cleveland Clinic. “Indoor Air Quality: Why It Matters and How to Improve It.” October 1, 2025. https://health.clevelandclinic.org/indoor-air-quality.
Harvard Health Publishing. “Easy Ways You Can Improve Indoor Air Quality.” February 15, 2021. https://www.health.harvard.edu/healthy-aging-and-longevity/easy-ways-you-can-improve-indoor-air-quality.
Senapathi, Venkatramanan, Bagyaraj Murugesan, Gurugnanam Balasubramaniam, Bairavi Swaminathan, Sivakumar Karthikeyan, Rahim Barzegar, and others. “Unveiling Air Quality Shifts during Diwali in Chennai Using Geospatial Insights for Pollution Assessment.” Discover Geoscience 3 (2025): 62. https://doi.org/10.1007/s44288-025-00174-x.
National Centre for Disease Control, Ministry of Health and Family Welfare, Government of India. Health Advisory on Air Pollution under NPCCHH. September 2022. https://ncdc.mohfw.gov.in/uploads/pdf/air4.pdf.
World Health Organization. “Air Pollution: Personal Interventions and Risk Communication.” October 4, 2024. https://www.who.int/news-room/questions-and-answers/item/air-pollution-personal-interventions-and-risk-communication.
United States Environmental Protection Agency. “Guide to Air Cleaners in the Home.” Accessed November 9, 2026. https://www.epa.gov/indoor-air-quality-iaq/guide-air-cleaners-home.
United States Environmental Protection Agency. “Sources of Indoor Particulate Matter (PM).” Accessed November 9, 2026. https://www.epa.gov/indoor-air-quality-iaq/sources-indoor-particulate-matter-pm.
United States Environmental Protection Agency. “Ozone Generators That Are Sold as Air Cleaners.” Accessed November 9, 2026. https://www.epa.gov/indoor-air-quality-iaq/ozone-generators-are-sold-air-cleaners.
United States Environmental Protection Agency. “Create a Clean Room to Protect Indoor Air Quality during a Wildfire.” Accessed November 9, 2026. https://www.epa.gov/emergencies-iaq/create-clean-room-protect-indoor-air-quality-during-wildfire.
Central Pollution Control Board. “National Air Quality Index.” Accessed November 9, 2026. https://airquality.cpcb.gov.in/AQI_India/.
Cummings, Bryan E., and Michael S. Waring. “Potted Plants Do Not Improve Indoor Air Quality: A Review and Analysis of Reported VOC Removal Efficiencies.” Journal of Exposure Science & Environmental Epidemiology 30 (2020): 253–61. https://doi.org/10.1038/s41370-019-0175-9.
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