Noise Pollution MCQ with answer and solution

Concept

The Noise Rules 2000 give four zones (industrial, commercial, residential, silence) with separate day and night limits in dB(A) Leq.

Step-by-step solution

1. Limits as per the Rules (day/night, dB(A) Leq): Industrial 75/70, Commercial 65/55, Residential 55/45, Silence 50/40. 2. Statement A gives 75/70 for commercial areas. These are industrial limits, so A is incorrect. 3. Statement B: day time is 6.00 a.m. to 10.00 p.m. This is correct. 4. Statement C: there are four categories of zones, not three. So C is also incorrect. 5. Statement D: silence zone is not less than 100 m around hospitals, educational institutions and courts. This is correct. 6. Both A and C are incorrect. A is chosen as the single answer (see note).

Explanation

For commercial areas, the noise limits are 65 dB(A) by day and 55 dB(A) by night. The values 75 and 70 belong to industrial areas, so statement A is wrong. Note that statement C is also wrong because the Rules give four zones, not three.

Why the other options are wrong

B: Correct. Day time is 6 a.m. to 10 p.m. C: Also an incorrect statement, because there are 4 zones (industrial, commercial, residential, silence). D: Correct. A silence zone extends not less than 100 m around hospitals, schools and courts.

Shortcut

Remember 75/70, 65/55, 55/45, 50/40 for Industrial, Commercial, Residential, Silence. Each step down is 10 dB in the day.

Common mistake

Mixing up the industrial and commercial limits, or forgetting the silence zone and counting only 3 zones.