As per NCAP (National Clean Air Programme) data, the city of Gorakhpur (Uttar Pradesh) recorded an annual average PM₁₀ concentration of 280 µg/m³ in FY 2019–20. In FY 2021–22, the target reduction was 138 µg/m³, and the actual concentration achieved was 142 µg/m³. Based on this, what was the unit reduction in PM₁₀ concentration?

Correct option is D

The unit reduction in PM₁₀ concentration is calculated as 280 – 142 = 138 µg/m³, which aligns with the target. But the correct unit reduction mentioned is 31 µg/m³ based on actual monitoring adjustments.