SSC Stenographer 2026 PYQ — Question 43

Solution: The correct answer is 8.
Explanation:
☛ India's National Air Quality Index (AQI) was officially launched in October 2014 under the Swachh Bharat Abhiyan.
☛ The calculation of AQI considers 8 criteria pollutants: Particulate Matter 10 (PM10), Particulate Matter 2.5 (PM2.5), Nitrogen Dioxide (NO2), Sulfur Dioxide (SO2), Carbon Monoxide (CO), Ozone (O3), Ammonia (NH3), and Lead (Pb).
☛ To calculate an AQI value, data for at least three pollutants must be present, with at least one of them necessarily being PM2.5 or PM10.
Extra Exam-Relevant Facts:
☛ The National AQI was developed by the Central Pollution Control Board (CPCB) in technical collaboration with IIT Kanpur.
☛ AQI classifies air quality into 6 color-coded categories: Good (0–50), Satisfactory (51–100), Moderate (101–200), Poor (201–300), Very Poor (301–400), and Severe (401–500).
☛ The index operates on the principle of "One Number- One Colour- One Description" to make air quality status easy for the common public to understand.
Important One-Liners for Upcoming Exams:
☛ In which year was the National Clean Air Programme (NCAP) launched in India? → 2019
☛ Which statutory organization operates the National Ambient Air Quality Monitoring Programme (NAMP)? → Central Pollution Control Board (CPCB)
☛ Under which legislation was the Central Pollution Control Board (CPCB) originally constituted in 1974? → The Water (Prevention and Control of Pollution) Act, 1974
☛ What is the AQI numerical range considered as 'Good'? → 0 to 50
☛ Which air pollutant has an affinity for human hemoglobin over 200 times greater than oxygen? → Carbon Monoxide (CO)