Noise-wise, India is among the most polluted countries in the world. The data on noise pollution is scarce, but whatever little exists for India shows that, in most cities, noise reaches dangerous levels. Sound levels are described in decibels (dB), with a logarithmic increasing scale and they double with every 10 dB increase. Thus, the noise loudness level at 40 dB is twice as that at 30 dB.

Sound level of normal human conversation is between 40-50 dB and that of rock or loud music concert is on an average 140 dB. Thus, rock music is approximately 500 times louder than human conversation!

Recent data shows that some Indian cities have noise levels greater than 75 dB and, during peak traffic jams, the deafening sound of horns blowing can reach 100-120 dB! Poor traffic sense, lax patrolling by police and bad roads exacerbate the noise pollution further. Medical data also shows that around 6-7% of India’s population is deaf, though the actual numbers may be much higher since most people never get tested for deafness.  

Scientists have shown that sound levels greater than 85 dB are dangerous to human health. In the long run, they damage hearing and increase stress levels. Studies all over the world have shown that increased sound levels cause elevated blood pressure, loss of sleep, increased heart rate, cardiovascular constriction and changes in brain chemistry.    

I feel the increase of anger and aggression in the city population is probably due to stress caused by noise pollution. This is further attested by medical studies worldwide which have shown that deafness (even partial) in early life leads to aggressive behaviour and dementia later in life. 

We hear sound through our ears where the pressure waves (sound) are converted into electrical signals and processed in the auditory centres of the brain. However, when the sound is loud enough, it also has the ability to pass through the human skull - the thinnest among all animals, and reach the brain directly.

Various scientific studies have shown the effect of mechanical forces on the working of the brain. Under various mechanical stresses brain chemistry gets altered, thus affecting neuron communications and general functioning of the brain. Loud noise vibrations passing through the skull can affect the brain - the softest tissue in the human body. In some ways, the effect of very loud sound may be similar to head trauma injury.  

Medical studies have also shown that with partial deafness, the brain starts using its other parts to compensate for this loss of input. This reduces working memory for processing higher thought functions, like cognition and analytical abilities, leading to dementia and other brain disorders.

Music, which is a sound, affects humans profoundly. Great music lifts the mood, is a balm to the soul and can have a profound effect on the wellbeing of humans in the long run. Similarly, “ugly and loud” sounds may affect the whole brain and, in the long run, have profound detrimental effects on human health. Even music, which may be soothing at low volumes, becomes cacophonous when played loudly.

Loud music has the same detrimental effect on nerves as multiple sclerosis. It destroys the insulation of nerve cells that go from ear to the brain. It is not necessary that only loud music heard in the open-air affects our health; even headphones with loud music has the same effect.

I feel the stress, foul mood and general aggressiveness comes from continuously being exposed to loud music. The young population which is constantly chatting or listening to music via headphones is susceptible to this phenomenon.

Another way sound pollution affects our health is by creating sleep deprivation.  Because of sound pollution at night, we do not get deep sleep. Studies have shown that without deep sleep the detoxification of brain does not take place; thereby creating long term stress which affects all aspects of mental and physical health.     

Studies have also shown that not only human but also animal health has been adversely affected by sound pollution. The beaching of whales and dolphins have been linked to Sonar experiments during various military exercises in oceans around the world. Similarly, biologists have found urban noise pollution affects adversely the communication signals of songbirds.  

The most important thing in fighting noise pollution is getting good data on it. Today there are innumerable sound-meter apps that can be downloaded on smartphones, making every person a mobile sound meter who can measure sound levels anywhere.

Thus, wherever we go and find the noise levels loud enough we should record them on our smartphones and upload them to a suitable centralized site. This can rapidly help create a sound-pollution map of the country.

Based upon this map, good noise abatement legislation can be formulated with very strict laws to limit the sound levels. The Indian judicial system takes ages to bring to justice cases and thus a much faster mechanism needs to be developed to curb the noise pollution. Heavy fines on the spot will deter noise polluters. Other effective methods can be devised to curb this pollution once all of us become aware of this nuisance. I feel true independence will be when we get freedom from noise pollution. Only then will we get on the path of emotionally happy and sustainable living in India.

(The writer is Director, Nimbkar Agricultural Research Institute, Phaltan, Maharashtra, He can be contacted at anilrajvanshi@gmail.com )