Who let the construction machines out?

The World Health Organisation estimates that some 120 million people worldwide have hearing difficulties. Loud noise can be a contributory factor for high blood pressure, heart disease and exacerbate mental health problems.Treating such a large number of persons is a huge social cost. Bangalore is under attack from the noise polluters and we are concerned. This city is crumbling under work conducted day and night on infrastructure projects. These projects threaten the productivity of the city as much as they claim to improve it. In the long term, infrastructure projects help the city but by then the residents may go deaf. On a daily basis, their efficiency declines.Night-time construction activity at many projects sites is affecting residents. They are robbed of their sleep and peace. A disturbed night is a potential disaster for the person the next morning. There is irritation, loss of concentration and the urge to flare up.We have had readers complain of excessive noise pollution along Metro projects and the flyover construction along Ring road. They encounter children becoming unmanageable at  night and cranky during the day. A prolonged loss of sleep is affecting the overall health of children in Jayanagar, Rajajinagar and Banaswadi.Strangely, our state pollution control board does not monitor sound pollution except during Deepavali. We may not blame them much because even the Central pollution control board does not have standards for noise pollution of infrastructure projects. The board restricts itself to vehicle sound and firecrackers. Other kinds of noise seem to be out of their hearing range!Consider the meticulous way the United States’ Department of Transport sets guidelines on noise and how to minimise it.The human ear does not judge sound in absolute terms, but instead senses the intensity of how many times greater one sound is to another. A decibel is the basic unit of sound level; it denotes a ratio of intensity to a reference sound. Most sounds that humans are capable of hearing have a decibel (dB) range of 0 to 140. A whisper is about 30 dB, conversational speech 60 dB, and 130 dB is the threshold of physical pain.Sound and noise are not the same thing, but sound becomes noise when it is too loud, it is unexpected, it is uncontrollable, it occurs unexpectedly, it has pure tone components.The noise levels generated during the construction process vary depending on the type of equipment and the nature of the work being performed. It should be recognised that noise impacts can be severe, especially during activites at night, and that in many cases simple noise mitigation strategies will not suffice.According to the US Department of Transport, some of the construction equipment noise control options are: Use rubber gaskets, fit with manufacturer-approved exhaust muffler, prohibit work within 200 ft of a noise-sensitive location during night hours, enclose with a noise tent, reduce idling and locate equipment away from noise-sensitive areas.Note the important point. The DOT says ‘impose seasonal limitations on construction noise, the spring or fall (autumn) are critical times in residential areas because windows are usually open at night’.Can we expect such sensitivity in Bangalore as we witness the metamorphosis of the city?