Air Quality Health Index Explained: Why India’s AQI Needs An Overhaul And Include Death Risk

We often hear about Delhi’s "very poor" air days, but what does that really mean for your health? A new study, published in IOP Science, titled: A framework for city-specific air quality health index: a comparative assessment of Delhi and Varanasi, India, says it may mean a lot more than just coughing, breathlessness or a minor discomfort. In fact, on some days, it could mean a higher risk of death.India’s current Air Quality Index (AQI), launched in 2015, was designed to simplify pollution levels and make it easy for people to understand the quality of the air they breathe. But a group of researchers now argue that this national index is outdated and dangerously vague when it comes to the actual health risk, particularly, the short-term risk of premature death.Their recommendation? Replace the one-size-fits-all AQI with a more precise, city-specific Air Quality Health Index (AQHI) that includes the risk of excess mortality. This, they say, will allow both the public and policymakers to take air pollution far more seriously.India's Air Quality Has Already Crossed WHO LimitsIndia’s worsening air quality is not just falling short of domestic health warnings, it is also regularly violating global safety standards.ALSO READ: India Air Pollution Levels Surpass UN's Safety StandardsAccording to the World Health Organization (WHO), India’s air pollution levels consistently surpass safe thresholds, posing a grave public health threat. This is not just a concern for Delhi, although it remains one of the world’s most polluted capitals. The issue extends far beyond its borders.Dr. Maria Neira, Director of WHO’s Department of Environment, Climate Change and Health, recently commented on this worrying trend. “There is a study which shows that we always focus on New Delhi when it comes to pollution, but I am afraid it is almost all of India where WHO standards on AQI are not implemented,” she said.Dr. Neira warned that while being slightly off WHO norms is still problematic, many Indian cities now drastically exceed safe levels. The solution, she said, lies in stronger political commitment to clean air initiatives and faster implementation of existing policies.40 Extra Deaths on a Single 'Severe' Pollution DayAccording to the new study, published on 22 July, this year, led by Dr Santu Ghosh from St John’s Medical College in Bengaluru, a severe pollution day in Delhi could lead to 16% higher mortality. In simple terms, if Delhi records an average of 250 deaths in a day, a severe air day may result in 40 additional deaths.That figure isn’t a vague long-term statistic, it reflects the immediate health impact of pollution. And yet, the current AQI doesn’t communicate this. A severe pollution reading today only warns that it "affects healthy people and seriously impacts those with existing diseases."By contrast, the proposed AQHI categorizes air days based on the short-term increase in excess mortality. Even a ‘moderate’ air quality day, according to this new index, comes with a 2 percent rise in daily deaths, and this risk increases as pollution worsens.Air Pollution: The India ProblemIndia’s air pollution is not just a seasonal or a regional issue. It is a year-round crisis that impacts vast sections of the population, especially in densely populated urban centres.Several regions across the country routinely record AQI values far beyond safe limits set by both Indian authorities and international health agencies. The WHO warns that even brief exposure to high levels of pollutants can trigger serious health issues, something that millions of Indians face daily.How AQHI Works and Why It’s DifferentUnlike the AQI, which uses a 0 to 500 scale, the AQHI operates on a simpler 0 to 100 range. More importantly, it’s tailored to each city using local data on pollution levels and mortality rates.The authors analyzed air pollution and mortality data from two cities: Delhi and Varanasi. Both were chosen for their political and public health relevance, Delhi being the national capital and Varanasi being the Prime Minister’s constituency, notes the study.The AQHI makes a strong case that even the same pollutant levels affect cities differently. For instance, if the PM2.5 level is 120 micrograms per cubic metre (a serious pollution level), the AQI might show 300 for both Delhi and Varanasi. But the AQHI, based on local health data, would show 46 for Delhi and 64 for Varanasi. In AQHI terms, Delhi’s reading would be ‘moderate,’ while Varanasi’s would be ‘poor’, reflecting a real difference in public health impact.Air Pollution Doesn’t Just Affect the LungsThe WHO also notes that the main pathway of exposure to air pollution is through the respiratory tract, and that breathing in polluted air leads to inflammation, oxidative stress, immune suppression, and even cellular mutations throughout the body.This can damage multiple organs, including the lungs, heart, brain, and more. WHO categorises air pollution as a risk factor for all-cause mortality, as well as for specific diseases such as stroke, ischaemic heart disease, chronic obstructive pulmonary disease (COPD), lung cancer, pneumonia, and even cataract. Pregnant women and children are especially vulnerable to its effects.Why the Current AQI Falls ShortIndia’s AQI uses health advisories from the US Environmental Protection Agency due to a lack of Indian studies when it was first launched. The 2015 document that introduced it even acknowledges this limitation. Since then, more local data has become available, but the AQI has not been updated.The AQI also does not mention mortality risk in any of its categories. At most, it notes minor breathing discomfort or effects on sensitive groups. But research shows that air pollution is the second leading risk factor for non-communicable diseases in India. It is directly linked to heart attacks, strokes, and respiratory diseases, all of which can become fatal quickly, especially in older adults or those with pre-existing conditions.What Can Be Done, Suggest Researchers Dr Sagnik Dey from IIT Delhi, one of the authors, compares this to tobacco: "With smoking, the blame can be put on the individual. But with air pollution, it’s a public issue, the government has to step in."One major challenge is access to mortality data, which is held by the Ministry of Health and the National Centre for Disease Control. However, researchers argue that once this data is made available, generating AQHI cut-offs for hundreds of Indian cities would take only a few months and cost very little.Making Air Warnings Harder to IgnoreThe AQI has become familiar in India over the past decade, even joked about by stand-up comics. But there’s little evidence that people or local authorities take its warnings seriously.By including death risk, the AQHI could serve as a more effective tool. The aim is not to replace the AQI completely, but to enhance it so that people understand the real health consequences of the air they breathe.

Air Quality Health Index Explained: Why India’s AQI Needs An Overhaul And Include Death Risk

Quick Stories

Boxer Conor Benn Considered Taking His Own Life After His Doping Test Results

After 212 Days, Has US Lost 'Elimination Status' For Measles As Outbreak Hit A Record High Of 1331 Cases

World's First Gonorrhea Vaccine Programme Rolled Out By NHS

Health Conditions A-Z

Breastfeeding Week: Breastfeed, Pumped Milk, Or Formula? Experts Weigh In On What Works The Best For A Mother And Her Child

Air Quality Health Index Explained: Why India’s AQI Needs An Overhaul And Include Death Risk

Vitamin B6 In Your Favorite Energy Drink Is Making You Jitter