Question

The permissible noise level in residential areas during night is approximately

• A. 75 dB
• B. 65 dB
• C. 45 dB
• D. 90 dB

Hint:

CPCB ambient noise limits: \[ \boxed{ \begin{array}{c|c|c} \textbf{Area} & \textbf{Day} & \textbf{Night}\\ \hline \text{Residential} & 55\ \text{dB} & 45\ \text{dB} \end{array} } \]

Answer 1

The Correct Option is C

Step 1: Recall the CPCB noise standards.
The Central Pollution Control Board sets separate day and night noise limits for different zones, since night time needs stricter control for peaceful sleep.
Step 2: Recall the residential zone numbers.
For residential areas, the daytime limit is 55 dB, and the night time limit is set 10 dB lower at 45 dB.
Step 3: Pick the matching value.
Since the question asks specifically about night time in a residential zone, the correct figure is 45 dB.
\[ \boxed{45\ \text{dB}} \]