Question

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : Air pollution causes significant deterioration in visibility.
Reason (R) : The rates of emissions or formation of pollutants greatly exceed the rate at which the pollutants are dispersed by winds or removed by chemical reaction.
In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Visibility is an equilibrium problem. If Input (Emissions) $>$ Output (Wind/Chemistry), the concentration grows and visibility drops.

Answer 1

The Correct Option is A

Concept: Atmospheric visibility is determined by the concentration of light-scattering particles (aerosols) in the air. This concentration is a balance between source strength and removal processes.

Step 1: Evaluate the Assertion.
Assertion (A) is correct. It is a well-observed environmental fact that pollutants like PM$_{2.5}$, sulfates, and nitrates scatter sunlight, which leads to "haze" and reduced visual range in cities.

Step 2: Evaluate the Reason.
Reason (R) is correct. Pollution levels only become "significant" and concentrated enough to ruin visibility when the emission rate is higher than the atmosphere's cleansing rate (wind dispersion or rain washout).

Step 3: Check for Causal Link.
Because the accumulation described in (R) is the physical reason why pollutant concentrations reach levels high enough to cause the visibility loss mentioned in (A), (R) is the correct explanation.