Why can the AQI go above 500?
CPCB's AQI scale stops at 500. True AQI extends the same scale instead of capping it. What a reading above 500 means, and why the advice stays the same.
CPCB’s scale stops at 500
India’s official AQI scale runs from 0 to 500. On the worst days, pollution can go beyond the level the scale was built to describe. Officially, those readings are capped at 500 and grouped as “severe plus”, which signals a public health emergency.
What True AQI does instead
Instead of capping the live reading, True AQI extends the same CPCB scale past 500. On the worst days you can see how far past Severe the air is, and whether it’s getting better or worse hour by hour.
This is not a different or stricter scale. Every reading up to 500 is exactly what CPCB’s scale gives. The official 24-hour average is always shown next to it.
The advice doesn’t change
Anything above 400 is Severe either way, and the advice is the same:
The bigger number is there so you can see what’s happening, not to alarm you.
Questions people ask
Is an AQI of 600 more dangerous than 500?
Yes, more pollution means more harm. But both are Severe, and the advice is the same: go out only if you must, and wear an N95 if you do.
Why doesn’t CPCB show readings above 500?
The scale was built to describe health effects up to that level. Anything beyond it is grouped as “severe plus”, which already signals a public health emergency.