SCHEDULE (See rule 3 (1) and 4 (1) Ambient Air Quality standards in respect of Noise Area Code Category of Area/Zone Limits in dB(A) Leq* Day Time Night Time (A) (B) (C) (D) Industrial area Commercial area Residential area Silence Zone 75 75 70 65 65 55 55 55 45 50 40 Note: -1. Day time shall mean from 6.00 a.m. to 10.00 p.m. 2. Night time shall mean from 10.00 p.m. to 6.00 a.m. 3. Silence zone is defined as an area comprising not less than 100 meters around hospitals, educational institutions and courts. The silence zones are zones, which are declared as such by the competent authority. 4. Mixed categories of areas may be declared as one of the four-abovementioned categories by the competent authority. *dB (A) Leq denotes the time weighted average of the level of sound in decibels on scale A which is relatable to human hearing. A “decibel” is a unit in which noise is measured. “A” in dB (A) Leq, denotes the frequency weighting in the measurement of noise and corresponds to frequency response characteristics of the human ear. Leq: It is an energy mean of the noise level over a specified period.
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