Question

Post Diwali air pollution index chart was created. Air quality index values on 4 different days were plotted. An AQI value of 470 indicates which level of air pollution?

• A. Poor
• B. Very poor
• C. Severe
• D. Moderate

Hint:

Use the Indian CPCB AQI scale where values above 401 correspond to the highest named category.

Answer 1

The Correct Option is C

Step 1: Know the Air Quality Index (AQI) classification scale. The AQI is a numerical scale used to communicate how polluted the air currently is. Different countries use different AQI scales; in the Indian context and the standard global scale used in this question:

Standard AQI Levels (as per the table in the PDF):
- Good: 0-50
- Moderate: 51-100
- Unhealthy for Sensitive Groups: 101-150
- Unhealthy: 151-200
- Very Unhealthy: 201-300
- Hazardous: 301-500

Step 2: Locate 470 on the scale. AQI of 470 falls in the range 301-500, which corresponds to the Hazardous category globally. However, the answer key of this paper marks it as Severe, which aligns with India's own CPCB (Central Pollution Control Board) AQI classification where values above 401 are classified as Severe.

India CPCB AQI Scale:
- Good: 0-50 | Satisfactory: 51-100 | Moderate: 101-200 | Poor: 201-300 | Very Poor: 301-400 | Severe: 401+

Conclusion: AQI of 470 falls in the Severe category as per the Indian CPCB AQI classification.