Ambient sound levels soaring in Bengaluru, six cities

Indian metropolitan cities, including Bengaluru, are extremely noisy with the ambient sound levels way above the recommended norms, says a national survey.

The survey was conducted by the national ambient noise monitoring network.

The results were obtained after scientists monitored the ambient noise levels in 10 sites of a city in seven cities since 2011.

The network began with 35 sites — five in each cities — but another 35 sites were added later.

After recording the sound levels in industrial, commercial, residential and silence zones of Delhi, Mumbai, Chennai, Kolkata, Bengaluru, Hyderabad and Lucknow, they found that only 14.3% of the sites — mostly in regulated industrial zones — met the ambient noise standards, even as there has been an increase in the noise level since 2011.

In Bengaluru, the ambient noise levels have increased significantly in the last five years at the Peenya industrial area. These is also a jump in the sound levels at night at Nisarga Bhawan residential site.

The noise levels at newly monitored sites — Yeshwantpur, RVCE and Nimhans— are higher than normal.

In Domlur, Nimhans, Peenya and Nisarga Bhawan, the increase in the sound level is most prominent between September and February.

In Yeshwantpur commercial site, the monthly average decibel level during the day is above 70 throughout the year, while the level comes down to 62 at night.

But even with an increase in the ambient sound levels since 2011, Peenya and Whitefield industrial areas have been able to meet the ambient noise norms. The scientists collected the data from four segregated zones in these metropolitan cities.

The sampling sites were distributed — industrial (12 sites), commercial (25), residential (16) and silence (17) — in these zones for better coverage. The permissible limits vary between 75 (day) and 70 (night) decibels for industrial, 65-55 for commercial and 55-45 for residential zones. For the silence zone, the limits are 50-40 decibels.

“It was observed that no site lying in commercial, residential and silence zones met the ambient noise standards,” the researchers from National Physical Laboratory, Delhi, Central Pollution Control Board and Delhi Technological University reported in the journal Current Science.

Only 7 sites (10%) met the target of 55 decibel at night for commercial areas.

DH News Service