For Prelims: Air Quality Index (AQI), PM2.5 and PM10, Graded Response Action Plan (GRAP), Swachh Bharat Mission, Full form of AQI, Nodal body for AQI, AQI launched in India, Number of AQI categories
For Mains: Air Quality Index, Graded Response Action Plan, CPCB, CAQM, PM2.5, Swachh Bharat, environmental governance, policy implementation
Source:
Indian Express
5 facts for one-day exams
SSC, railway, police and teaching exams ask direct questions like these.
- India's AQI was launched in 2014 under the Swachh Bharat campaign.
- The AQI has six categories: Good, Satisfactory, Moderate, Poor, Very Poor, and Severe.
- The AQI is determined by the highest sub-index among eight pollutants, not an average.
- GRAP Stage III restrictions include a ban on BS-III petrol and BS-IV diesel four-wheelers.
- The Central Pollution Control Board (CPCB) records India's official AQI.
Why in the news?
Delhi's AQI is in the 'Very Poor' category with several stations crossing 400. Differences between government and private readings arise due to varying AQI scales, breakpoints, and measurement methods. GRAP Stage III restrictions are in force, and understanding the AQI calculation and GRAP stages is crucial for exams.
Summary
- India's AQI, launched in 2014 under Swachh Bharat, uses a six-category colour-coded scale from Good (0-50) to Severe (401-500).
- The AQI is determined by the highest sub-index among eight pollutants (PM2.5, PM10, NO₂, SO₂, O₃, CO, NH₃, Pb), not an average.
- GRAP Stage III restrictions include curbs on non-essential construction and demolition activities, a ban on BS-III petrol and BS-IV diesel four-wheelers in Delhi and specified NCR districts, and hybrid classes for children up to Class V, among other measures.
- Private platforms show higher readings because India caps its AQI at 500 and uses different breakpoint thresholds than international scales.
Highlights
Delhi AQI at 370 (Very Poor)
Several monitoring stations crossed 400 (Severe) post-Diwali, but the city average remained in 'Very Poor'.
Why Private Readings Differ
India caps AQI at 500 and uses different breakpoint thresholds than international scales, causing private platforms to show higher numbers.
GRAP Stage III in Force
Restrictions include bans on BS-III petrol/BS-IV diesel vehicles, non-essential construction, and hybrid classes for children up to Class V.
Background
Delhi's air quality deteriorates every winter due to vehicle emissions, construction dust, industrial activity, and crop-residue burning. Cooler temperatures and weak winds trap pollutants, worsening the situation. The AQI system was launched in 2014 to standardise air quality reporting under Swachh Bharat.
Key Analysis and Impact
The discrepancy between CPCB and private AQI readings highlights methodological differences. India uses a capped scale (max 500) with its own breakpoint thresholds, while platforms like AQI.in use US EPA standards that allow readings beyond 500. This can confuse the public and undermines trust in official data. The highest sub-index determines the overall AQI, not an average, so one very high pollutant can drive the index up.
Way Forward
Atmospheric scientist Gufran Beig has questioned India's decision to cap AQI at 500, suggesting that uncapped readings would better reflect actual pollution levels. Sustained emission reductions, not just emergency GRAP measures, are needed. China's example of stricter industrial controls and cleaner transport offers lessons, but India's unique governance and pollution sources require a tailored approach.
India's AQI Categories
| Category | AQI Range | Colour |
|---|---|---|
| Good | 0-50 | Green |
| Satisfactory | 51-100 | Light Green |
| Moderate | 101-200 | Yellow |
| Poor | 201-300 | Orange |
| Very Poor | 301-400 | Red |
| Severe | 401-500 | Maroon |
Background GK
Textbook concepts you need to understand this news
- Air Quality Index (AQI)
- A number used to communicate how polluted the air currently is, based on concentrations of major pollutants. Higher values indicate worse air quality.
- PM2.5 and PM10
- Particulate matter (PM) with diameters of 2.5 micrometres or less (PM2.5) and 10 micrometres or less (PM10). PM2.5 can enter the bloodstream and cause serious health issues.
- Graded Response Action Plan (GRAP)
- A set of emergency measures implemented in Delhi-NCR by the Commission for Air Quality Management (CAQM) when AQI crosses certain thresholds. It has four stages with progressively stricter restrictions.
- Swachh Bharat Mission
- A nationwide cleanliness campaign launched by the Government of India in 2014, under which the AQI was also launched.
Facts to remember
Tap a card to see the answer. Try to recall it first.
How exams will ask this
- Data: India's AQI categories: Good (0-50), Satisfactory (51-100), Moderate (101-200), Poor (201-300), Very Poor (301-400), Severe (401-500).
- Nodal Body: Central Pollution Control Board (CPCB) for AQI; Commission for Air Quality Management (CAQM) for GRAP.
- GRAP stages and their triggers: GRAP has four stages with progressively stricter measures but does not provide the numeric triggers for Stages I–III; it only mentions Stage IV can be invoked when AQI exceeds 450 or forecasts indicate it will. Authorities may also invoke measures in advance based on forecasts.
Don't make this mistake!
Examiners may swap 'highest sub-index determines AQI' with 'average of all pollutants'. They may also confuse GRAP stages: Stage III bans BS-III petrol/BS-IV diesel vehicles, not all vehicles. The AQI cap of 500 is often mistaken as a fixed maximum concentration rather than a reporting limit.
Write these in mains answers
- Air Quality Index, Graded Response Action Plan, CPCB, CAQM, PM2.5, Swachh Bharat, environmental governance, policy implementation
Stuck? Get it in one tap
The Air Quality Index (AQI) is a number that tells you how clean or polluted the air is. India uses a scale from 0 to 500, with higher numbers meaning worse air. On November 9, 2026, Delhi's average AQI was 370, which is 'Very Poor'. Some private apps showed much higher numbers because they use different scales that do not stop at 500. When the AQI gets bad, the government activates GRAP, which is a set of rules to reduce pollution.
- India's AQI was launched in 2014 under the Swachh Bharat campaign.
- The AQI has six categories: Good, Satisfactory, Moderate, Poor, Very Poor, and Severe.
- The AQI is determined by the highest sub-index among eight pollutants, not an average.
- GRAP Stage III restrictions include a ban on BS-III petrol and BS-IV diesel four-wheelers.
- The Central Pollution Control Board (CPCB) records India's official AQI.
- Environment: Air pollution and Air Quality Index
- Governance: Environmental governance and GRAP
Related concepts: Air Quality Index (AQI), PM2.5 and PM10, Graded Response Action Plan (GRAP), Swachh Bharat Mission
Practice questions
Pick an answer, then read the explanation.
- Q1Easy
Which body is responsible for implementing the Graded Response Action Plan (GRAP) in Delhi-NCR?
Explanation: CAQM is the statutory body that implements GRAP in Delhi-NCR. CPCB monitors air quality and sets standards, but GRAP enforcement falls under CAQM. The Ministry of Environment oversees policy, and DPCC works under CPCB at the state level.
- Q2Hard
Consider the following statements regarding the Air Quality Index (AQI) in India:
- 1.The AQI is determined by calculating the average of all major pollutant sub-indices.
- 2.India's AQI scale is capped at 500, while some international platforms allow readings beyond this limit.
- 3.The AQI was launched in 2014 as part of the Swachh Bharat campaign.
Which of the statements given above is/are correct?
Explanation: Statement 1 is incorrect: the AQI is determined by the highest sub-index among pollutants, not an average. Statement 2 is correct: India caps its AQI at 500. Statement 3 is correct: the AQI was launched in 2014 under Swachh Bharat.
- Q3Medium
What was Delhi's 24-hour average AQI recorded by the CPCB on November 9, 2026?
Explanation: The CPCB recorded Delhi's 24-hour average AQI at 370 on November 9, 2026, which falls in the 'Very Poor' category (301-400). 450 is the threshold for GRAP Stage IV, 382 was the AQI on November 6 when Stage III was invoked, and 500 is the cap of India's AQI scale.
- Q4Medium
Why do private monitoring platforms like AQI.in show substantially higher AQI readings than the CPCB for the same location?
Explanation: Private platforms may use different monitoring locations, averaging periods, and measurement methods. More importantly, they use different AQI scales (e.g., US EPA standards) with different breakpoint thresholds that allow readings beyond India's cap of 500. Option (A) is speculative and not supported by the news.
Frequently asked questions
1. What was Delhi's AQI on November 9, 2026?
The CPCB recorded Delhi's 24-hour average AQI at 370, which falls in the 'Very Poor' category (301-400).
2. Why do private platforms show higher AQI readings than the CPCB?
Private platforms use different AQI scales (e.g., US EPA standards) with different breakpoint thresholds and do not cap readings at 500 like India's official scale.
3. What restrictions are in place under GRAP Stage III?
GRAP Stage III bans BS-III petrol and BS-IV diesel four-wheelers in Delhi-NCR, non-essential construction, and mandates hybrid classes for children up to Class V.
4. Who implements the Graded Response Action Plan in Delhi-NCR?
The Commission for Air Quality Management (CAQM) implements GRAP in Delhi-NCR.
All sources
- Original9 November 2026 · Read story
