What Does AQI 100, 200, 300 and 500 Mean?
Understand what different AQI levels mean for your health and what actions you should take at each range.
AQI Ranges and What They Mean
The Air Quality Index runs from 0 to 500, with each range carrying specific health implications. Here is what each level means for you and your family.
AQI 0–50: Good
Air quality is considered satisfactory and poses little or no health risk. This is rare in most Indian cities outside of monsoon seasons or in hill stations.
- Health impact: None
- Action: Enjoy outdoor activities normally
- Typical in India: Hill stations, coastal areas during clean wind periods, immediate post-monsoon
AQI 51–100: Satisfactory
Acceptable air quality. Some pollutants may be a concern for a very small number of hypersensitive individuals.
- Health impact: Minor breathing discomfort for sensitive people
- Action: No restrictions for most people
- Typical in India: Many cities after rain, suburban areas on good days
AQI 101–200: Moderate
This is where air quality starts to degrade noticeably. Sensitive groups should consider reducing prolonged outdoor exertion.
- Health impact: Breathing discomfort for people with lung or heart conditions
- Action: Reduce prolonged outdoor activities if you are sensitive
- Typical in India: Common in cities like Mumbai, Chennai, and Bangalore on average days
AQI 201–300: Poor
At this level, air quality begins to affect the general population. Prolonged exposure may cause noticeable health effects.
- Health impact: Breathing discomfort for most people on prolonged exposure
- Action: Avoid prolonged outdoor exertion; wear a mask outdoors
- Typical in India: Common in Delhi-NCR during winter months, many industrial cities
AQI 301–400: Very Poor
This triggers health warnings. The entire population is likely to be affected.
- Health impact: Respiratory illness on prolonged exposure; children and elderly at significant risk
- Action: Avoid all outdoor activities; use air purifiers indoors; wear N95 masks
- Typical in India: Delhi in November–December, severe smog episodes
AQI 401–500: Severe
Emergency conditions. Even healthy people will experience health effects.
- Health impact: Serious respiratory effects; healthy people affected by prolonged exposure
- Action: Stay indoors; run air purifiers at maximum; avoid all physical activity outdoors
- Typical in India: Delhi during peak winter inversion, post-Diwali in many northern cities
Beyond 500: Severe Plus
India sometimes records AQI levels exceeding 500, particularly in Delhi-NCR. While the standard scale stops at 500, readings of 600, 800, or even higher have been reported. At these levels, schools are typically closed, construction is banned, and emergency measures under the Graded Response Action Plan (GRAP) are triggered.
How to Respond at Each Level
| AQI | Mask Needed? | Outdoor Exercise? | Air Purifier? |
|---|---|---|---|
| 0–50 | No | Yes | Not needed |
| 51–100 | No | Yes | Optional |
| 101–200 | Sensitive groups only | Reduce if sensitive | Recommended |
| 201–300 | N95 recommended | Avoid | Yes |
| 301–400 | N95 mandatory | Avoid completely | Yes, run on high |
| 401–500 | N95 mandatory | Do not go out | Yes, run continuously |
Key Takeaways
- AQI 0–50 is “Good” and safe for everyone; rarely seen in major Indian cities
- AQI 101–200 (“Moderate”) is the most common range across urban India
- AQI 201+ affects the general population, not just sensitive groups
- At AQI 301+, avoid all outdoor activities and use air purifiers
- India regularly records AQI beyond 500, triggering emergency GRAP measures