What is Noise? State the effects of it and mention the measures to control it.

(N/A) In India,the Air (Prevention and Control of Pollution) Act came into force in $1981$ and was amended in $1987$ to include noise as an air pollutant.
- Noise is an undesired high level of sound. $A$ high sound level greater than $150 \ dB$ or more,generated by the takeoff of a jet plane or rocket,may damage eardrums,thus permanently impairing hearing ability.
- Noise also causes sleeplessness,increased heart rate,and altered breathing patterns,thus causing considerable stress to humans.
- Control Measures:
$(i)$ Reduction of noise in industries can be achieved by using sound-absorbent materials or by muffling noise.
$(ii)$ Stringent adherence to laws laid down in relation to noise,such as the delimitation of horn-free zones around hospitals and schools.
$(iii)$ Setting permissible sound levels for firecrackers.
$(iv)$ Restricting the use of loudspeakers after a specific time.