21 September 2026 · Faheem M
Delhi AQI: Current Air Quality, Forecast & Health Guide
Understand Delhi AQI, air quality forecasts, pollution levels, health effects, and practical ways to reduce exposure when air pollution rises.
Delhi's air quality can change significantly throughout the day. Pollution levels can also vary considerably between different parts of the city, which means a single AQI number does not always represent the conditions at every location.
This guide explains how to check Delhi's current AQI, understand the forecast, interpret AQI categories, identify the pollutants behind poor air quality, and reduce exposure when pollution levels rise.
Check the latest Delhi AQI: Delhi Live AQI
Delhi AQI Today
Delhi's air quality can vary between monitoring stations and change throughout the day.
AQIRadar's Delhi air-quality page aggregates readings from multiple monitoring stations and provides a city-level view alongside station-level information. This is useful because pollution near a busy road, industrial area or construction site can differ from readings in a residential area.
Check Delhi's current AQI on AQIRadar
When checking Delhi's air quality, look at:
Current AQI
AQI category
PM2.5 concentration
PM10 concentration
Monitoring location
Whether pollution levels are increasing or decreasing
Short-term air-quality forecast
AQIRadar's research on why AQI changes explains that traffic, construction, wind direction, local weather, regional pollution transport and monitoring-station location can all contribute to differences in readings.
What Does Delhi's AQI Mean?
The Air Quality Index (AQI) converts concentrations of several pollutants into a simplified number that helps people understand overall air quality.
India's National Air Quality Index uses six main categories:
AQICategoryPossible health impact0–50GoodMinimal impact51–100SatisfactoryMinor breathing discomfort to sensitive people101–200ModerateBreathing discomfort for people with lung or heart disease, children and older adults201–300PoorBreathing discomfort with prolonged exposure301–400Very PoorRespiratory illness with prolonged exposure401–500SevereRespiratory effects even in healthy people
These categories and associated health impacts come from India's Central Pollution Control Board (CPCB).
If you want to understand how the index is calculated and what the numbers mean in more detail, see AQIRadar's guides to What Is AQI? and AQI Levels Explained.
AQI is not the same as PM2.5
An AQI value is an index, not a measurement of a single pollutant.
Several pollutants can contribute to AQI, including:
PM2.5
PM10
Nitrogen dioxide (NO₂)
Sulfur dioxide (SO₂)
Carbon monoxide (CO)
Ozone (O₃)
Ammonia
Lead
The pollutant with the highest individual sub-index can determine the overall AQI.
Which Pollutants Matter Most in Delhi?
Delhi's air contains a mixture of pollutants, and the dominant pollutant can change depending on the location and conditions.
PM2.5
PM2.5 refers to fine particles with an aerodynamic diameter of 2.5 micrometres or smaller.
These particles are small enough to penetrate deep into the respiratory system. Research has linked exposure to fine particulate pollution with cardiovascular and respiratory effects.
Because PM2.5 is particularly important for health, it is useful to look beyond the overall AQI and check the actual PM2.5 concentration.
Learn more in AQIRadar's guide to PM2.5 and PM10.
PM10
PM10 includes particles with an aerodynamic diameter of 10 micrometres or smaller.
PM10 can include dust, construction particles and other coarse and fine particles. PM2.5 is a subset of PM10, meaning the two measurements should not be treated as completely separate types of pollution.
Delhi AQI Forecast: What Should You Look For?
Air-quality forecasts estimate how pollution levels may change based on emissions, atmospheric conditions, weather and other factors.
When checking a Delhi AQI forecast, look for:
Expected AQI category
PM2.5 and PM10 trends
Wind conditions
Rainfall
Atmospheric mixing
Regional pollution
Whether pollution is expected to improve or deteriorate
Weather and AQI are connected — but not identical
A clear day does not automatically mean clean air.
Likewise, rain or stronger winds can sometimes help reduce particulate concentrations, but the effect depends on the intensity of rainfall, wind, atmospheric conditions and subsequent emissions.
This is why an AQI forecast should be checked separately from a weather forecast.
AQIRadar's Why Does AQI Change Every Day? guide explains how weather, wind, traffic, construction and regional pollution can interact to change air quality.
Why Does Delhi's AQI Change So Much?
Delhi's air quality is influenced by multiple factors rather than one single source.
1. Traffic
Vehicle activity can contribute pollutants including particulate matter and nitrogen oxides.
Traffic-related pollution can also vary depending on traffic volume, road design and proximity to major roads.
2. Construction and road dust
Construction activity and resuspended road dust can contribute to particulate pollution, particularly PM10.
3. Wind
Wind can disperse pollutants and transport pollution from one location to another.
Low-wind conditions can allow pollutants to accumulate closer to the ground.
4. Rain
Rain can remove some particulate matter from the atmosphere.
However, rainfall does not guarantee clean air, and its effect depends on weather and emission conditions.
5. Atmospheric conditions
The ability of the atmosphere to mix pollutants vertically can influence how concentrated pollution becomes near the surface.
6. Regional pollution
Delhi's air quality is affected not only by emissions generated within the city but also by pollution transported from surrounding areas.
7. Seasonal conditions
Delhi experiences significant seasonal changes in air quality. Cooler conditions and atmospheric stagnation can contribute to severe pollution episodes, while weather patterns and emissions can influence air quality throughout the year.
Is Delhi AQI Safe for Outdoor Exercise?
There is no single AQI number at which outdoor exercise becomes universally "safe" or "unsafe" for every person.
The appropriate precautions depend on:
Current AQI
Dominant pollutant
Duration of exposure
Exercise intensity
Location
Individual health
Age
At higher pollution levels, strenuous outdoor exercise can increase exposure because exercise increases breathing rate and the amount of air inhaled.
CPCB's AQI health guidance indicates that prolonged exposure at the Poor level can cause breathing discomfort, while Very Poor air quality is associated with respiratory illness on prolonged exposure.
If AQI is elevated, consider reducing prolonged or strenuous outdoor exercise and checking the latest air-quality readings before heading outside.
How Does Delhi Air Pollution Affect Health?
Air pollution can affect the respiratory and cardiovascular systems.
The World Health Organization states that air pollution is associated with major health risks and that evidence supports effects across cardiovascular, respiratory and other body systems.
Fine particulate matter is particularly important.
The U.S. EPA reports that both short- and long-term exposure to fine particle pollution have been associated with cardiovascular effects, including heart attacks, heart failure and stroke, as well as respiratory effects such as asthma attacks, coughing, wheezing and shortness of breath.
Short-term exposure
Elevated particle pollution can be associated with:
Coughing
Wheezing
Shortness of breath
Airway irritation
Asthma exacerbation
Increased respiratory symptoms
Long-term exposure
Longer-term exposure to particulate pollution has been associated with cardiovascular and respiratory health effects. The WHO's global air-quality guidelines reflect evidence showing health effects at lower pollutant concentrations than earlier guidelines recognized.
Who Should Be More Careful When Delhi AQI Is High?
Some groups can be more vulnerable to the effects of air pollution.
These include:
Children
Children can be particularly sensitive to air pollution because their respiratory systems are still developing.
Older adults
Older adults may be more vulnerable, particularly when underlying heart or lung conditions are present.
People with heart or lung conditions
Particle pollution can aggravate existing cardiovascular and respiratory conditions.
People exercising outdoors
Running, cycling and other strenuous activities increase breathing rate and therefore increase the amount of air inhaled.
WHO's current evidence review identifies children, pregnant women, older people and people living with chronic disease among groups at greater risk from air pollution.
How to Protect Yourself When Delhi AQI Is High
1. Check AQI before going outside
Don't rely on yesterday's AQI.
Check the current reading and, when available, the short-term forecast before planning prolonged outdoor activities.
2. Reduce strenuous outdoor exercise
If pollution is elevated, consider moving intense workouts indoors.
This is particularly relevant for activities such as running and cycling that substantially increase breathing rate.
3. Reduce exposure near heavy traffic
Spending less time directly beside busy roads can help reduce exposure to traffic-related pollution.
4. Pay attention to PM2.5
Don't look only at the overall AQI.
PM2.5 is particularly important because fine particles can penetrate deeply into the respiratory system and have been associated with cardiovascular and respiratory effects.
5. Think about indoor air quality
Going indoors does not automatically eliminate exposure.
Outdoor pollution can enter buildings, while indoor activities such as cooking and combustion can generate additional particles.
Read Indoor vs Outdoor Air Quality to understand why indoor conditions can differ from outdoor AQI. AQIRadar notes that ventilation, cooking, combustion, filtration and building characteristics all influence indoor air quality.
6. Reduce indoor PM2.5
If outdoor pollution is high, reducing the amount of particulate matter entering your home can be useful.
AQIRadar's How to Reduce PM2.5 Inside Your Home covers approaches such as source control, ventilation and filtration.
7. Consider filtration
Particle air cleaners can reduce indoor particulate concentrations when appropriately sized and operated.
Performance depends on factors including airflow, room size, filter efficiency, operating time and filter condition.
Learn more about HEPA filters and how particle filtration works.
8. Don't assume windows should always be open or closed
Ventilation can improve indoor air when outdoor air is relatively clean.
During an outdoor pollution episode, however, opening windows can increase the amount of outdoor pollution entering the building.
The right approach depends on outdoor conditions as well as indoor pollution sources.
Delhi AQI vs Indoor Air Quality
One of the most important things to understand is that outdoor AQI does not tell you exactly what the air inside your home contains.
Indoor air can be affected by:
Outdoor pollution entering through windows and doors
Cooking
Smoking
Incense and other combustion sources
Cleaning activities
Poor ventilation
Dust
Filtration
Building characteristics
For example, if outdoor PM2.5 is high, closing windows may reduce outdoor particle infiltration. But if cooking is generating PM2.5 indoors, closing the windows alone will not eliminate the indoor source.
This is why indoor air quality needs to be considered separately from outdoor AQI.
Read AQIRadar's Indoor vs Outdoor Air Quality guide for a deeper explanation. AQIRadar specifically notes that outdoor AQI should not be treated as a direct measurement of indoor air quality.
When Is Delhi's Air Quality Usually Worst?
Delhi's air quality changes seasonally.
The most severe pollution episodes are often associated with cooler periods when atmospheric conditions can limit pollutant dispersion and allow particulate pollution to accumulate.
Several factors can combine during these periods, including:
Low wind speeds
Atmospheric stagnation
Temperature-related atmospheric conditions
Local emissions
Regional pollution transport
Seasonal combustion sources
However, pollution is not exclusively a winter problem.
Dust, traffic, construction, weather and other emissions can contribute to elevated pollution during other periods as well.
For this reason, checking the current AQI is more useful than assuming air quality based solely on the season.
How to Read Delhi AQI Correctly
Don't look at the AQI number alone.
A better approach is:
AQI → Category → Dominant pollutant → Trend → Exposure
For example:
AQI: Check the latest reading
Category: Good / Satisfactory / Moderate / Poor / Very Poor / Severe
Dominant pollutant: Check the pollutant breakdown
Trend: Is AQI increasing or decreasing?
Exposure: How long will you be outside and what will you be doing?
This gives you more useful information than simply asking whether the AQI is "high."
Why Can Two Websites Show Different Delhi AQI Numbers?
This is a common source of confusion.
Different AQI services may use:
Different monitoring stations
Different geographic coverage
Different averaging methods
Different update times
Different AQI calculation methodologies
AQIRadar's research also highlights monitoring-station location as one factor that can explain differences between readings. A monitor near a busy road can report different pollutant concentrations from one in a residential area.
When comparing two AQI websites, check whether each one is reporting:
a specific monitoring station, a city average, a regional average, or an AQI calculated using a different methodology.
Delhi AQI Forecast: How to Plan Your Day
Instead of asking only:
"What is Delhi's AQI today?"
ask:
What is the AQI right now?
Is it getting better or worse?
Which pollutant is driving it?
What does the short-term forecast indicate?
Will I be outdoors for a long time?
Am I exercising or doing physically demanding work?
Is there a better time of day for the activity?
Can I reduce indoor exposure if outdoor pollution rises?
This approach turns AQI information into something practical.
Frequently Asked Questions
What is the AQI in Delhi today?
Delhi's AQI varies by monitoring station and can change throughout the day. Check the latest reading on AQIRadar's Delhi AQI page or official CPCB monitoring data before making decisions about outdoor activities.
Is Delhi AQI 200 dangerous?
An AQI between 201 and 300 falls into India's Poor category. CPCB describes prolonged exposure at this level as potentially causing breathing discomfort.
The appropriate precautions depend on the duration of exposure, activity and individual circumstances.
Is it safe to exercise outside in Delhi?
It depends on the current AQI, pollutant levels and exercise intensity. As pollution increases, prolonged or strenuous outdoor activity can increase exposure.
Check the current AQI before exercising outdoors.
What is the best time to go outside when Delhi AQI is high?
There is no universal time that is always cleanest.
AQI can change throughout the day depending on traffic, weather, wind and atmospheric conditions.
Check the hourly pollution trend for your location rather than assuming that morning or evening is always better.
Does rain improve Delhi's AQI?
Rain can help remove particulate matter from the atmosphere, but its effect varies depending on rainfall intensity, wind, atmospheric conditions and subsequent emissions.
A rainy day should not automatically be interpreted as having clean air.
Is PM2.5 more dangerous than PM10?
PM2.5 particles are smaller and can penetrate deeper into the respiratory system. Fine particulate pollution has strong evidence linking exposure with cardiovascular and respiratory effects.
Both PM2.5 and PM10 are important pollutants, but they measure different particle-size ranges.
Should I use an air purifier when Delhi AQI is high?
A properly selected particle air cleaner can reduce indoor particulate concentrations. Its effectiveness depends on factors such as airflow, room size, filter efficiency, operating time and filter condition.
See AQIRadar's guide to HEPA filters for more information.
Should I keep my windows closed when Delhi AQI is high?
If outdoor particulate pollution is elevated, closing windows can reduce outdoor pollution entering your home.
However, indoor sources such as cooking can also generate PM2.5.
The appropriate approach therefore depends on both outdoor and indoor conditions.
Delhi AQI: The Bottom Line
Delhi's air quality can vary substantially between locations and throughout the day.
The most useful way to understand Delhi AQI is not to focus on one number in isolation. Check the current AQI, monitoring location, dominant pollutant, recent trend and forecast together.
When pollution levels rise, reducing prolonged outdoor exposure, avoiding strenuous outdoor exercise and paying attention to indoor air quality can help reduce unnecessary exposure.
For people with heart or lung conditions, children and older adults, elevated particulate pollution deserves particular attention because these groups can be more vulnerable to its effects.
And remember: today's AQI is only a snapshot. Delhi's air quality can change with weather, wind, emissions and atmospheric conditions.
Related AQIRadar Resources
If you want to understand Delhi's air quality in more detail, these guides provide additional information:
Sources & References
Central Pollution Control Board (CPCB) — National Air Quality Index. Provides India's AQI categories and associated health-impact descriptions.
World Health Organization (WHO) — Global Air Quality Guidelines. Evidence-based guideline levels for PM2.5, PM10, ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide.
World Health Organization (WHO) — Health effects of air pollution: evidence and implications. Current evidence covering respiratory, cardiovascular, cerebrovascular and other health effects and vulnerable populations.
U.S. Environmental Protection Agency (EPA) — Particle Pollution Exposure. Evidence on cardiovascular and respiratory effects associated with particle pollution.
U.S. Environmental Protection Agency (EPA) — Health and Environmental Effects of Particulate Matter. Information on particle size, respiratory effects and cardiovascular impacts.
AQIRadar — Delhi live AQI monitoring and station-level information.
AQIRadar — Why Does AQI Change Every Day? Explains the role of traffic, construction, wind, weather, regional pollution and monitoring-station location.
Medical & Editorial Note
This article is intended for general educational purposes. It does not diagnose or treat medical conditions and should not replace advice from a qualified healthcare professional.
AQI and pollutant readings are dynamic and can vary by monitoring station and reporting method. Always check current official monitoring data before making decisions based on today's air quality.
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