Diwali’s lights may have dimmed, but the haze they left behind still hangs heavy. As Delhi chokes under an AQI of 331 and Mumbai hovers around 160, taking a breather, quite literally, has never felt more urgent. The antidote to this post-festive smog might just lie beyond the metro skylines, in towns where the air still smells of rain, not residue. For those seeking refuge from the greyness of city life, several Indian cities promise a lungful of clarity. Each city on this list has recorded an AQI below 30, offering crisp, clean air and a much-needed reset. As of 9am on October 23, these are the cities with the cleanest air in India:
Shillong, Meghalaya AQI: 12
Madikeri, Karnataka AQI: 12
Tiruchirappalli, Tamil Nadu AQI: 16
Thanjavur, Tamil Nadu AQI: 17
Puducherry, Puducherry AQI: 18
Gangtok, Sikkim AQI: 21
Udupi, Karnataka AQI: 24
Tirumala, Andhra Pradesh AQI: 25
Coimbatore, Tamil Nadu AQI: 26
Ramanathapuram, Tamil Nadu AQI: 26
Kollam, Kerala AQI: 30
Bengaluru, Karnataka AQI: 30
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Read Also : AQI score: 8 Indian cities with the best air quality index that you can visit to actually breathe a little
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What is the Air Quality Index?
An Air Quality Index (AQI) is a quantifiable measure of the air pollution level in an area via eight pollutant categories which is denoted as a composite figure for clear communication.
But beyond telling you how clean or polluted your air is, the AQI of your city also helps you plan your travel, commute and any outdoor activities which might be impacted.
On a larger scale, this data actually helps governments to take measures to improve the air we breathe. In India, for example, this data has aided in identifying non-attainment cities aka cities that have fallen short of meeting the National Ambient Air Quality Standards (NAAQS) for five years straight. With this list, mitigation of air pollution has been able to take a tailored, city-wise approach over the past few years. This involves a Graded Action Plan Response in New Delhi to address the rising pollution levels with respect to the AQI categories (ranging from good to severe). Globally, this data from across the world also helps formulate and revise the WHO Global Air Quality Guidelines (GAQG), which currently recommend air quality levels for six major pollutants.
How is AQI evaluated?
A look outside your window right now might give you obvious cues about what the air is like. But indexing air quality is a lot more meticulous than noticing dust or smog. It requires an air monitoring scale which can measure the concentration of air pollutants over a specified averaging period. The results you get are grouped into ranges, and each range is colour coded, labelled in terms of quality and assigned a standardised public health advisory.
A drastic increase in AQI levels could have potential health hazards from immediate discomfort like eye irritation, an itchy throat and allergies to more serious respiratory complications for those with existing medical conditions or compromised immunity. And as the air quality deteriorates to very poor and severe, even the most healthy begin to run a risk for developing chronic respiratory diseases.
Currently in India, we use the AQI scale established by the United States Environmental Protection Agency (EPA) which ranges from zero to 500. EPA launched its AQI way back in 1999, which was then adopted by many counties across the world. But quality of air and the factors that affect it differ across regions, which is why most of them have altered the index to suit their requirements.
Now this particular scaling system is linear. So while your city could be affected by multiple elements, the AQI scale will report only the ones with the highest values as recorded over a one-hour average. Apart from major emissions from the brick-making industries near Delhi or the stubble burning in Punjab that make the headlines, your city could be affected by solid fuel combustion, biomass, diesel generators, wood burning, construction and other irritants. In India, all of these are regulated under eight pollutant categories, namely: ground-level ozone, particulate matter (split into PM10 and PM2.5), carbon monoxide, sulphur dioxide, lead, ammonia and nitrogen dioxide.
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Read Also : Top 10 Most Polluted Cities in the World Based on AQI⁺ (US) [Updated 2025]
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Here’s a handy breakdown of how to analyse the AQI in your city:
0-50: Low risk
51-100: Satisfactory
101-200: Moderate
201-300: Poor
301-400: Very poor
401-500: Severe
AQI is subject to change depending on time of day. This story was updated as of 9am on 23 October, 2025.
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NOTE – This article was originally published in CNTraveller and can be viewed here