A study published in Current Science says that ambient noise levels in India's metropolitan cities are way above safe limits. The study, conducted by the National Physical Laboratory, the Central Pollution Control Board and Delhi Technological University, found that fewer than 10 of the 70 sites in seven cities that were monitored Bengaluru, Chennai, Delhi, Hyderabad, Kolkata, Lucknow and Mumbai met the ambient noise standards. Worryingly, no site lying in commercial and residential zones met the noise standards. This was the case even in 'silent zones' too. The decibel (dB) level in 'silent zones' should not exceed 50dB during the day and 40 dB at night. However, the study found that noise levels in these zones ranged from 56-77 dB range during the day and 51-77 dB at night. Interestingly, industrial sites did better -- 10 of the 12 industrial sites studied met the ambient noise norms, with sound levels below the standard of 75 dB during the day and 70 dB at night. Noise levels in Bengaluru have increased significantly. In Domlur, Nimhans, Peenya and Nisarga Bhawan, the increase was most pronounced in the September-February period.
Noise is not only annoying but it also harms health. It hampers sleep, makes us irritable, damages hearing and triggers anxiety. The sound of honking vehicles can get on one's nerves and trigger rage. Human hearing is amazing. We can hear the rustle of leaves and the slightest of whispers. We can listen to a person speak at 60 dB for hours. Loud music at 110 dBs in a night club is bearable for some time. Sound becomes painful at 120 dB, and at 140 dB it can tear the eardrum. Chronic exposure to 85 dB for eight hours can cause hearing loss. Noise-induced hearing loss is irreversible.
The Noise Pollution (Regulation and Control) Rules, 2000, provides different decibel norms for different zones in cities. Unfortunately, these norms are not being enforced. The government must get vehicle manufacturers to reduce the noise and vibration levels of vehicles. Importantly, the ban on multi-tone horns must be enforced. In Bengaluru in particular, several failures have contributed to making this once quiet city one of the noisiest -- commercial activity in residential zones, youngsters flaunting banned two-stroke bikes by revving them up to intolerable levels, the rampant use of diesel generator sets, loud music on festivals and functions, etc. The government must act to enforce the norms in each of these cases. But reducing noise pollution is not the government's responsibility alone. People must act, too, to make our cities quieter. It is one of the things that will improve quality of life in the city.