SSC CGL 2025 Tier-I · 21 September 2025, Shift 3 · General Awareness · Question 22 of 100

We transcribed this text from the pictures on a candidate's response sheet for this shift; the answer is the key SSC colour-marked on that sheet. Solution last reviewed 11 September 2026.

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Read the below statements marked as Assertion (A) and Reason (R). Mark the correct options: Assertion (A): AQI value above 400 is classified as 'Severe'. Reason (R): Such levels cause respiratory effects even on healthy individuals.

(a)Both A and R are true, and R is the correct explanation of A.
(b)Both A and R are true, but R is not the correct explanation of A.
(c)A is true, but R is false.
(d)A is false, but R is true.

Answer

Why

Correct — A. A is true: India's National Air Quality Index, launched in 2014, labels the band 401–500 'Severe'.

R is true, and it is the reason for the label. The bands carry likely health impacts, and the note for Severe reads: 'May cause respiratory impact even on healthy people, and serious health impacts on people with lung/heart disease.' Option (a).

Why the others are wrong

(b)
Both A and R are true, but R is not the correct explanation of A. — R is not incidental. The index attaches likely health impacts to every band, and 'even on healthy people' is the phrase it uses for the Severe band.
(c)
A is true, but R is false. — R is true: the index's health note for Severe says it may cause respiratory impact even on healthy people, with effects possible even during light physical activity.
(d)
A is false, but R is true. — A is true: 401–500 is Severe, the top band, and 301–400 is Very Poor. Any value above 400 therefore falls in Severe.

Concept

India's National Air Quality Index was launched in 2014 as 'One Number-One Colour-One Description'. It tracks eight pollutants: PM₁₀, PM₂.₅, NO₂, SO₂, CO, O₃, NH₃ and Pb.

A sub-index is worked out for each pollutant, and the worst sub-index becomes the AQI.

The six bands are Good (0–50), Satisfactory (51–100), Moderately polluted (101–200), Poor (201–300), Very Poor (301–400) and Severe (401–500).

The step below Severe is worded differently. Very Poor (301–400) may cause respiratory illness on prolonged exposure. Severe may affect even healthy people, even during light physical activity.

Key facts

The National Air Quality Index was launched in New Delhi on 17 October 2014 by the Environment Ministry.
It covers eight pollutants: PM₁₀, PM₂.₅, NO₂, SO₂, CO, O₃, NH₃ and Pb.
The overall AQI is the worst of the pollutant sub-indices.
AQI 401–500 is Severe and 301–400 is Very Poor.

Study next

Graded Response Action Plan (GRAP) for Delhi-NCRNational Clean Air Programme (NCAP)PM₂.₅ versus PM₁₀: particle sizes and health effects

Common traps

Placing Severe at 301–400: that band is Very Poor.
Rejecting R as the explanation because AQI is computed from concentrations: each band is defined alongside its likely health impact.

AQI also appears at 15 Sep 2025, 12:30, GA Q.19, an Assertion-Reason item on Delhi's AQI levels whose Reason is keyed false.

Related PYQs

No directly related past PYQ was found.

Topic: Scientific Research — all 178 SSC CGL questions on it, every solved shift.