Air pollution and your pet in India: the chronic exposure, the indoor air, and what the AQI number actually means

What air pollution does to a dog or a cat, and what is actually demonstrated

Air pollution damages the lungs of dogs living in polluted cities, and the proof came from dogs that looked completely well. That is the finding to carry into the rest of this page.

The foundational work is a canine study, not a human one. Researchers examined 152 clinically healthy stray mongrel dogs, 109 of them from southwest and northeast metropolitan Mexico City and 43 from three less polluted Mexican cities. The lungs of the city dogs showed patchy chronic mononuclear cell infiltrates, bronchiolar epithelial and smooth muscle hyperplasia, peribronchiolar fibrosis and microthrombi, and bronchoalveolar lavage showed significant numbers of alveolar macrophages undergoing proliferation. The paper's own title calls dogs a sentinel species for chronic exposure to air pollutants.

Read the phrase clinically healthy again. These animals were not coughing. Nobody had brought them to a vet. The remodelling was already there, which is the single most useful thing an Indian owner can know, because it means the absence of a cough is not evidence that the air is fine.

South Asia has one study of its own and it is grimmer. Of 76 stray dogs admitted with respiratory distress in the Kathmandu Valley between July and November 2020, 24 recovered and 52 died. All 52 were necropsied, and 25 of them had gross lung and lymph node lesions strongly indicating pulmonary anthracosis, the deposition of carbon in lung tissue. In all 25, the pleural surface carried diffuse black pigmentation and the lymph nodes carried black particles; 68 percent had interstitial pneumonia and 64 percent had emphysema with broken alveolar septa.

The largest study says something more awkward than the headlines

The biggest dataset in this field measures visits, not diagnoses, and its respiratory finding is null. Across roughly 1.86 million cat visits and 4.96 million dog visits in the United Kingdom between January 2017 and September 2022, each extra microgram per cubic metre of PM2.5 averaged over the preceding week was associated with 0.70 percent more visits for cats and 0.71 percent for dogs. Moving from below 5 micrograms to the 40 to 50 range implies 30 to 40 percent more expected visits.

Now the part the pages quoting that number leave out. The category driving the whole effect is the vague one, Other Unwell, at 1.3 percent for cats and 1.2 percent for dogs. Respiratory visits, about 1 percent of all visits, showed no significant effect. Two readings are honest. Either the respiratory category is too small to detect anything, or the animals are turning up unwell in ways nobody is coding as a breathing problem. The paper also disagrees with itself in two places, describing over seven million visits where the species table sums to about 6.82 million, and giving the same-day effect as 2 percent in the results and 0.2 percent in a footnote. We print that rather than tidying it.

Why your pet's dose is not your dose on the same walk

Your pet takes a larger and dirtier dose than you do on the identical walk, for two measured reasons and one that nobody has measured yet.

Start with breathing rate, because it is the one you can check tonight. A normal respiratory rate for dogs is 12 to 30 breaths per minute. For a healthy adult human at rest it is 12 to 18. The ranges overlap at the bottom and diverge sharply at the top, and a dog that is trotting, sniffing hard or excited sits at the top of its range while you walk at the bottom of yours.

Then height. The nearest measured evidence is not about dogs, and we say so plainly, but it is the right shape. Across 89 single runs covering 145 kilometres of a 2.1 kilometre urban route, fine particle concentration at pram height was always higher than at adult breathing height, by up to 44 percent. In a double pram, the lower seat carried about 72 percent more ultrafine particles than the upper one.

The composition changed with height too, and that is the detail worth keeping. Electron microscopy of the coarse fraction found brake wear and tyre wear predominating at baby height, while adult height carried a relatively larger share of earth crust elements. A dog's nose sits at or below pram height on an Indian footpath, so the fraction it inhales is weighted towards the metal-bearing wear particles thrown off by the vehicles passing a metre away, not the ordinary dust you smell.

The number nobody has measured

No study has measured the inhaled dose of a dog walking an Indian street. We looked, and the gap is real rather than a failure of searching: the canine pathology comes from Mexico and Nepal, the household work comes from Taiwan, the visit data comes from Britain, and the low-height measurements come from pushchairs in a British town. Treat every number on this page as the right direction with an unknown multiplier for India, and treat anybody who gives you a precise Indian dose figure for a dog as having invented it.

• Count the breaths, not the symptoms. A sleeping dog or cat consistently over 30 breaths a minute is outside the normal range and worth a call.
• Treat the kerb as a different place from the park, because the gradient over a metre of height and ten metres of distance is larger than the gradient across a city.
• Assume the small dog gets the worse air, since a Pomeranian's nose is lower than a Labrador's and the low layer is the dirty one.
• Add the sniffing, which is the whole point of a walk for a dog and also the activity that pulls the most air through the nose closest to the ground.

The season is months long, and it is not only Delhi

Plan for a season rather than a night, because the north Indian bad-air window runs from roughly late October into February and the southern and western cities have a quieter version of the same curve.

This page deliberately does not cover the festival spike. The particulate measurements for Diwali night, the post-festival recovery window and the paw-washing routine for cracker residue are already set out in Diwali pet safety tips for dogs and cats in India, and the cold-weather side is in winter care for dogs in India. What those pages describe is an event. What this page describes is the baseline the event sits on top of.

The clearest public marker of the season is the government's own escalation ladder. The Commission for Air Quality Management runs a Graded Response Action Plan for the National Capital Region in four stages, tied to Delhi's air quality index: Stage I for Poor at 201 to 300, Stage II for Very Poor at 301 to 400, Stage III for Severe at 401 to 450 and Stage IV for Severe Plus above 450. Each stage's restrictions stack on the ones below it.

One feature of that plan is genuinely useful to a pet owner and almost nobody uses it. Stages are invoked in advance of the index reaching the projected level, on the basis of a day-to-day forecast from the India Meteorological Department and IITM. A GRAP order is therefore a forecast you get free, a day or more before the number on your phone moves. If you live in Delhi, Gurugram, Noida, Faridabad or Ghaziabad, a Stage III order is your cue to change the week, not to check the app again.

Mumbai, Bengaluru, Chennai, Kolkata, Pune, Hyderabad and Ahmedabad

Outside the National Capital Region there is no GRAP and no equivalent trigger, so you watch the index yourself. The practical difference between the metros is the shape of the year rather than the existence of a problem, and the shape is something you read off your own city's monitoring station rather than off a national headline. Mumbai and Pune in Maharashtra, Ahmedabad in Gujarat and Kolkata in West Bengal each have their own curve. Chennai in Tamil Nadu and Bengaluru in Karnataka have flatter ones, which makes them easier to be complacent about and no cleaner beside a bus corridor.

Do the same reading for the monsoon, because the seasonal low and the seasonal high both matter to a walking routine. Pull up twelve months of your station's history once and note which months sit lowest. In most Indian cities those humid monsoon months are the easiest walking of the year for a pet's lungs, and they are also when a flat stands open for ventilation, which is correct and is covered from the other side in monsoon care for dogs in India. The mistake is carrying the open-window habit into November without thinking about it.

How to read India's air quality index as a pet owner

To read the air quality index as a pet owner, understand three things about the number before you act on it: what concentration it stands for, which pollutant produced it, and what period it covers.

India's National Air Quality Index runs in six categories, and each one is anchored to a concentration. The Central Pollution Control Board publishes the breakpoints, and for a pet owner the PM2.5 column is the one that matters, because fine particles are the fraction that reaches deep into a lung.

Two mechanics of the index change how you should use it. The first is that the sub-index for each pollutant is calculated from its 24-hourly average concentration, and the worst sub-index becomes the AQI for that location. So the number is a maximum, not an average of your air, and it may be driven by ozone or nitrogen dioxide on a day when particulate is tolerable.

The second mechanic is the one almost nobody states. CPCB's real-time AQI is a running average: the board's own explanation is that the AQI at 6 am on a day will incorporate data from 6 am on the previous day to the current day. The figure you check before a 6 am walk therefore describes the last twenty-four hours, including yesterday evening's traffic, and tells you very little about the air in the next thirty minutes. CPCB also notes that real-time data is fed directly from the analysers without scrutiny and may not be fit for statutory purposes.

There is no AQI threshold for a dog, and that absence is the finding

No Indian authority publishes an air quality threshold for animals, and we are not going to invent one. We read CPCB's Broad Guidelines for Public looking for a protective rule and found that the document is about emissions rather than exposure: it asks the public to keep vehicles maintained, get PUC checks, follow lane discipline, avoid prolonged idling, and during severe or very poor AQI to minimise travel, use public transport, carpool and avoid larger vehicles. There is no health-protection advice in it for a person, and no mention of an animal anywhere in it. The GRAP schedule does not mention animals either.

So here is a defensible rule rather than a fabricated number. Borrow the state's own ladder, because it is forecast-driven, published daily and already calibrated to the same index. Treat GRAP Stage I, the Poor band at 201 to 300, as the point where a brachycephalic, elderly or airway-compromised animal shortens its outing. Treat Stage II as the point where every animal shortens. Treat Stage III as the point where exercise moves indoors and outings become toilet breaks. Outside the National Capital Region, apply the same band numbers from your own city's published index, because the bands are national even where the enforcement plan is not.

Timing the walk when the published number cannot tell you the hour

Time the walk off your own city's hourly curve rather than off the headline index, because the index is a trailing twenty-four hour average and the hourly pattern differs between cities and between streets.

Indian advice on walk timing flatly contradicts itself, and the two pages are both on page one. Dr Vinod Sharma, a veterinarian at DCC Hospital in New Delhi, told The Indian Express that owners should avoid late evenings and early mornings, opt for normal walks at a time when smog is less, and not make pets run, because running increases the amount of toxic air they breathe. The Indian pet brand page ranking third on the Delhi query advises the opposite, telling readers that if they must go out they should do it early morning or late evening when traffic and smog may be slightly lower. Neither page shows its working, and only one of them can be right for your street.

The resolution is not a rule, it is a measurement you make once. Most Indian city index sites and apps publish an hourly series for individual monitoring stations. Open the station nearest you, look at the last seven days of hourly values, and find the dip. It will usually be a block in the afternoon in the northern winter and a different block elsewhere. Write the hour down and keep it for the season.

1. Pick your station, not your city. A citywide figure averages a monitor on a quiet campus with one on a flyover; the one two kilometres from your gate is the one to read.
2. Read seven days of hourly values once, in the first week of the season, and settle on a walk timing block rather than deciding each morning.
3. Shorten before you cancel. A dog that never goes out develops a different set of problems, and a short sniffing walk moves far less air through the lungs than a run of the same length.
4. Drop the running, the fetch and the dog park first, since intensity multiplies the dose faster than duration does.
5. Keep the toilet breaks whatever the number says, and make them brief and close to home on the worst mornings.

Night walks need a separate thought in Indian cities, because a large share of Indian dog walking happens after dark for reasons of heat and work hours, and the evening traffic peak and the overnight build-up of particulate overlap with it. The visibility, street dog and heat arguments for and against the night walk are set out in walking dog at night safety; the air argument is simply that the late evening is rarely the clean hour it feels like.

Route, traffic corridors and road dust

Change the route before you change anything else, because the gradient between a main road and an internal lane is the largest single reduction available to you and it costs nothing.

The measurement behind this is the height study again. Brake wear and tyre wear predominated in the coarse particles sampled at low height beside a road, while the sample at adult height carried a relatively larger share of crustal material. Brake and tyre wear are not tailpipe emissions, so they do not disappear as traffic electrifies, and they are produced where vehicles brake, which means signals, speed breakers, bus stops and the entrance to your own colony.

Road dust is the other half of the problem and India regulates it explicitly. Stage I of the GRAP schedule, invoked at the Poor band, requires dust mitigation at construction and demolition sites, covered transport of construction materials and waste, anti-smog guns, periodic mechanised sweeping and water sprinkling on roads, and strict enforcement of the prohibition on open burning of biomass and municipal solid waste. That list is a map of what is in the air at nose height on an ordinary Indian street.

Five route changes that cost nothing

1. Move one street in. An internal colony lane with parked cars and no through traffic is a different place from the arterial road it connects to.
2. Walk the inside edge of the footpath, not the kerb, and put yourself between the dog and the traffic where the path allows it.
3. Avoid the active construction site entirely, including the week after it finishes, because the stockpile and the lorry route outlast the work.
4. Skip the stretch being swept or sprinkled. Mechanised sweeping lifts road dust while it works, so the hour after is better than the hour during.
5. Report the burning leaf pile rather than walking past it, since open burning of biomass and waste is prohibited under the first stage of the plan.

Indoor air, where your pet actually spends its life

Indoor air deserves more of your attention than the walk does, because your pet is home for most of the twenty-four hours and an Indian home adds sources of its own on top of whatever comes in from the street.

Two in five Indian households still cook on something other than a clean fuel. India's own National Family Health Survey put households using clean fuel for cooking at 58.6 percent in 2019 to 2021, up from 43.8 percent in 2015 to 2016 and 25.6 percent in 2005 to 2006, across a sample of 636,699 households. Cooking smoke is therefore not a marginal indoor source in this country, it is the normal condition of 41.4 percent of homes, and the animal in the kitchen doorway is in it for every meal of every day.

The second Indian source is the one nobody quantifies, and it has been quantified. Burning a single mosquito coil releases the same PM2.5 mass as burning 75 to 137 cigarettes, and the formaldehyde from one coil can be as high as that released from burning 51 cigarettes. The authors tested four common Chinese brands and two Malaysian ones, found the Malaysian coils generated more of the measured pollutants, and concluded that exposure to the smoke of coils similar to those tested can pose significant acute and chronic health risks.

The mosquito coil is a nightly, months-long exposure, which is the point

Apply the duration, not the single-coil figure. A coil is not lit once; in most of India it is lit at dusk through the whole mosquito season, in the room where people sleep, which is usually the room where the dog or cat sleeps too. The animal is at floor level, under the drifting smoke, for eight hours, every night, for months. That is the exact shape of exposure the Mexico City dogs had from their street, delivered indoors, and no one has measured it in an animal.

A caution on scope, because the coil has a second and separate hazard. The pyrethroid chemistry in coils and liquid vaporisers, and what it does to a cat that chews a refill, is a toxicology question rather than an air quality one, and it is covered in indoor cat safety in India. This section is only about what the smoke does to a lung.

Where this page revises our own Diwali guide

Our Diwali page states that the indoor evidence for dogs is weaker than for cats, and a second study published since then tightens that. The best-known household study found an association in cats and none in dogs. The follow-up, a prospective study of 20 dogs and 16 cats with existing lower airway disease, measured PM2.5 at the animal's own head height in five frequented spots of each home, and found that dogs from homes above 35 micrograms per cubic metre had a median total nucleated cell count in bronchoalveolar lavage fluid of 622 cells per microlitre against 344 in the cleaner homes, p = 0.023.

That is a measured airway response in dogs, so the correct statement is now narrower than ours was. Household PM2.5 is not associated with whether a dog has respiratory disease, and it is associated with how inflamed the airway of an already-ill dog is. The authors conclude that poor indoor air quality may exacerbate airway disease in pets and should not be ignored in modern society. The same paper counts five high-VOC households in its text while its table lists four dogs in that group, an inconsistency we are flagging rather than smoothing over.

Air purifiers, costed honestly in rupees

An air purifier measurably cuts indoor particulate in a South Asian home and does not make the air clean, and both halves of that sentence matter before you spend anything.

The nearest measurement to an Indian home is a Dhaka pilot, and we are labelling it as Bangladeshi rather than passing it off as Indian. Researchers gave households pollution monitors and randomised an offer of a free air purifier, then logged daily particulate from 25 November 2022 to 31 March 2023 across 2,332 observations. Providing a purifier cut household PM2.5 by about 74 micrograms per cubic metre, a 27 percent reduction off a control mean of 279. The authors' own conclusion is blunt: it did not bring air pollution levels down to levels considered healthy by international standard.

Hold those numbers against the Indian band table above. A home at 279 micrograms per cubic metre of PM2.5 is above the 250 at which the Severe band begins; the same home with a purifier running sits at about 205, which is inside the 121 to 250 Very Poor band and more than three times the 60 micrograms per cubic metre at which the Satisfactory band tops out. A purifier moves an animal from catastrophic to bad. It is worth doing and it is not a solution.

The disagreement inside the only South Asian measurement

The same study contains two incompatible accounts of how much people actually run the thing, and the honest move is to print both. At endline, 81 percent of households reported using the purifier six or seven days a week and 19 percent reported not using it at all. Smart socket data from the same households showed 41 percent using it more than two hours a day, which the authors call a lower bound, and the text elsewhere says only about half used it for more than two hours a day on average. The authors themselves flag likely over-reporting in the survey answers.

Cost is not the barrier the gap suggests. The study found electricity costs for a purifier are small, approximately half the cost of running a ceiling fan, and concluded that monetary factors are unlikely to explain the low usage. Purchase price is the visible number. On one large Indian retailer's air purifier category page for pet owners, read on 21 October 2026, listed prices ran from ₹6,899 to ₹86,990, a spread of more than twelve times across the same first page.

• Put it in the room the animal sleeps in, with the door shut, rather than the drawing room nobody sits in. A purifier works on the volume it can actually turn over.
• Budget for the filter, not the box. A replacement filter is a recurring cost in rupees every several months and an unchanged filter is an ornament.
• Run it on the bad nights rather than buying a bigger one, because the measured gap between households is in hours of use, not in machine size.
• Expect a fall, not clean air. The one South Asian trial moved a home 27 percent and left it well above any health standard.

The dog mask question, answered without mockery

Do not put a dog mask or pet respirator on an animal, for three reasons that are about physiology and standards rather than about the product being silly.

An Indian veterinarian has gone on the record on this and should be quoted rather than paraphrased. Dr Vinod Sharma of DCC Hospital in New Delhi told The Indian Express that he does not think any mask, N95 or otherwise, should be put on a pet, and that pets should mostly be kept indoors with the air purifier switched on. He gave three reasons. Dogs pant with their mouths open and regulate body temperature through the blood vessels of the tongue. Unlike a person, a pet cannot take a mask off when it feels suffocated. And there are, in his words, no well-designed masks in India, with little known about the scientific way to put a mask on a pet.

The fit problem is structural, not a manufacturing failure to be corrected. A respirator only filters what it seals, and a canine muzzle varies from a Pug's to a Saluki's across the same species, so a device sold in four sizes cannot seal across that range. Dr Sharma makes the same point from the clinic, noting that masks are not appropriately designed for pets like pugs and bulldogs and that most animals will not tolerate something strapped to their face. If your dog already has brachycephalic obstructive airway syndrome, adding resistance at the nose is the opposite of helpful.

The thermoregulation problem is the one that makes a well-sealed mask worse than a badly sealed one. A dog sheds heat by panting, which means moving a large volume of air over a wet tongue. Anything that restricts that flow restricts cooling, and India is a country where a walk is warm in most months and most places. A mask that genuinely sealed would be a heat risk, and a mask that does not seal does nothing. There is no version of the product that escapes both.

1. Shorten the outing instead of filtering it, because duration is the variable you control cleanly.
2. Reroute to a lower-traffic street, which is the single largest free reduction available.
3. Retime to your station's hourly dip, read once at the start of the season.
4. Filter the room, not the animal, since that is the intervention with a measured effect behind it.

Which animals are hit first, and the signs to watch for

Watch the flat-faced, the old, the very young and the already-diagnosed first, and watch all of them by counting breaths rather than by waiting for a cough.

Five groups carry more risk than the rest, and four of them you already know about. Brachycephalic dogs and cats work harder to move air on a clean day, so any added resistance eats a margin that is already small; our condition page on brachycephalic obstructive airway syndrome covers the mechanism. Senior animals lose respiratory reserve, which is part of the wider picture in senior dog care in India. Puppies and kittens have developing airways. Animals with an existing diagnosis, including tracheal collapse in dogs or feline asthma, start from a worse place. The fifth group is the one people miss: the high-drive dog that runs flat out for twenty minutes pulls far more air through its lungs than a dog ambling beside you, so intensity puts a healthy young animal in the risk group for that half hour.

Counting breaths is the one measurement you can take at home

To count a resting respiratory rate, watch the chest rise and fall while the animal is asleep or settled and count for a full minute. A normal rate for dogs is 12 to 30 breaths per minute. Do it once a week through the season and write the number down, because a trend in your own animal is worth more than any band table, and you cannot see a trend without a baseline taken when things were fine.

Cats hide this better and accumulate differently. A review of indoor organic pollutants found cats carrying far higher serum burdens than dogs, with median concentration ratios running to roughly 1,760-fold for brominated flame retardants, 58-fold for PCBs and 17-fold for organochlorine pesticides, and attributed the gap partly to grooming and partly to metabolism, noting that dogs have the ability to metabolise most accumulated indoor organic pollutants. The review's own caveat is that those comparisons come from studies in different parts of the world. The practical reading is that a cat is a better indicator of what is in your house than your dog is, and that a cat coughing is easy to mistake for a hairball attempt that produces nothing.

One more honest note on attribution. Nothing on this page lets you say that the air caused your animal's cough. The largest dataset found no significant effect in the respiratory visit category specifically, the household study enrolled only animals that were already ill, and the Nepali necropsy series never measured the dogs' exposure at all. Reducing exposure is well justified. Blaming the air for a specific illness, in front of a vet, is not.

If your household is a flat rather than a house, the practical geometry of which room to filter, where the animal sleeps and where the kitchen smoke goes is worked through in keeping a dog in a flat in India.

The dogs with no indoor option

Free-ranging dogs carry this exposure continuously, and the uncomfortable fact is that almost everything we know about chronic air pollution in dogs was learned from them.

Look again at the two pathology studies. The 152 animals in the Mexico City work were stray mongrel dogs. The 76 animals in the Kathmandu Valley work were street dogs. The reason this literature exists at all is that free-ranging dogs can be necropsied in numbers and have lifelong, unprotected, documented exposure to a single city's air. The animals that taught us about chronic exposure are the same animals living on Indian streets, and nobody has run the equivalent study in Delhi, Mumbai, Kolkata or Kanpur.

Be honest about what a feeder can do, because the list is short and pretending otherwise helps nobody. You cannot give a street dog clean air. You can reduce the things that stack on top of it, and you can make the animal easier to treat if it does become ill.

• Keep water out and fresh, because well-hydrated airways clear irritants better than dry ones and water bowls go dusty fast in a dry season.
• Do not burn rubbish, leaves or packaging on your own street, which is both prohibited under the first stage of the plan and the closest source to the dogs sleeping there.
• Feed away from the kerb rather than beside the traffic lane, so the animal is not eating in the brake-wear layer.
• Notice the cough. A free-ranging dog with a persistent cough has nobody taking a weekly breath count, so the feeder is the only monitor it has.
• Know the number of a local vet and a rescue group before the season rather than during it.

The practice of feeding, the law, and the civic arguments are covered in feeding community dogs in India and free-ranging dogs in India. This page adds only the air, and the point that the evidence base for the air is built on these animals.

What nobody has measured, and what we could not verify

Four things are missing from this field, and naming them is more useful than filling the gaps with a confident guess.

First, there is no published Indian veterinary study of companion animals and air pollution that we could find. The canine pathology is Mexican and Nepali, the household work is Taiwanese, the vet-visit economics is British. In a country where 99 percent of the world's population already lives in places that miss the World Health Organization's air quality guideline levels, and where ambient air pollution is estimated to have caused 4.2 million premature deaths worldwide in 2019, the absence of an Indian animal dataset is a gap in the national record rather than a gap in our searching.

Second, no Indian authority has published an animal-facing air quality advisory. We read CPCB's public guidelines under the index and found emission advice with no mention of animals, and we read the current GRAP schedule and found no mention of animals either.

Third, nobody has measured the inhaled dose of a dog at nose height on an Indian street. The 44 percent figure this page uses comes from prams in a British town, and it is the closest available proxy rather than an Indian measurement.

Fourth, no trial has measured a respiratory outcome in a dog or a cat from any intervention described here. Air purifiers have a measured effect on room particulate and no measured effect on an animal. Route change, walk timing and source removal are reasoned from exposure, not from outcomes. That gap is being filled commercially rather than scientifically: the Indian pet brand page ranking third on the Delhi query devotes five product blocks to hemp seed oil, bone broth, oral rehydration salts and two turmeric and ashwagandha supplements as smog-season interventions, and answers its own question about whether supplements help or are marketing with a yes and no citation. Bonbeno names no supplement here, because no trial supports one.

The honest one-line summary of the air pollution effect on pets in Indian cities is that the direction of harm is established, the Indian magnitude is not, and the interventions that cost nothing are worth making anyway.