Like all bad news, this one's come through loud and clear. And that's the terrible irony of it, for Delhiites have started complaining of age-related hearing loss as early as 60 years of age, says a study conducted by the Centre for Occupational and Environmental Health at Maulana Azad Medical College (MAMC). Presbycusis (age-related hearing loss) is the cumulative effect of ageing on hearing. It is a progressive age-related hearing loss which generally sets in after the age of 75 years.



In Delhi, however, such cases are being reported at the age of 60. "The ENT department at MAMC observed symptoms of presbycusis in people at the age of 60, which should ideally begin at 75. We scanned the data of last 10 years and observed that the age for the medical condition has actually come down by almost 15 years," said Dr T.K. Joshi, director of the Centre for Occupational and Environmental Health, MAMC. Researchers studied thousands of cases of presbycusis reported at MAMC over the past 10 years and came to the conclusion that one out of four patients developed hearing-related problem in early 60s.

"This is happening due to very high pollution levels in the city even in residential areas. Noise trauma is one of the major reasons triggering Presbycusis among people. Other reasons triggering the problem are poor diet, smoking and hypertension among others," said Dr Joshi. MAMC conducted noise mapping studies across Delhi for three years to measure the levels of noise pollution in different areas. The study was commissioned by Delhi Pollution Control Committee (DPPC). Residential areas where the noise levels were recorded to be dangerously high are central Delhi, Rohini, Pitampura, Dwarka and IGI Airport.



Norms not met



"We measured noise levels all over Delhi and didn't find a single area where the Central Pollution Control Board (CPCB) norms were met. The levels when measured were found anywhere between 80 decible (dB) and 93 dB at different times day and night. For instance, in Dwarka we found the noise levels were as high as 93 dB. This level is deafening," said Dr Joshi. In residential areas, 40 to 50 dB is considered moderate noise level during the day. At night, the limit comes down by five notches to 40 to 45 dB.



Sixty to 80 dB is considered loud noise, while anything above 90 dB is dangerous and can cause damage to ears if continued for a long time.



"We also noticed noiseinduced hearing loss in some patients. It happens due to exposure to either a sudden, loud noise or exposure to loud noises for a long period of time. A dangerous sound is anything that is 85 dB or higher," said Dr Joshi. "Higher noise can precipitate heart problems too. Stress hormones are released when a person is exposed to noise pollution. During the study, we found that Delhi is a highly uncivilised city. Unnecessary honking adds to noise pollution," said Dr Joshi. Experts say Delhi is in dire need of acoustical solutions.



Not only people on roads but also those working or dwelling on higher floors (as high as 10th floor) in traffic-heavy areas face high noise levels that can cause health problems. The Transport Planning Division, Council for Scientific and Industrial Research (CSIR) and Central Road Research Institute (CRRI) and Department of Civil Engineering, Jamia Millia Islamia, recently conducted noise mapping in the Capital and found noise levels at various locations scaling up to 83 dB. They have given recommendations for the noise barriers at various busy areas in the city.



"Increasing noise level due to road traffic is a major concern for the quality of life in urban areas. It can be reduced to some extent by adopting mitigating measures such as providing noise barriers and proper traffic management," said Nasim Akhtar, Transport Planning Division, CSIR-CRRI.



CSIR, CRRI and Jamia University conducted two types of noise mapping - vertical and horizontal. It gave them a clear picture of exposed areas and the number of people exposed to varying noise levels. "At Nehru Place, on the road, the noise levels varied between 80 and 82.6 dB(A), while till the10th floor, noise levels were more than 70 dB(A). This means people whose are staying till that floor are exposed to that level of noise," Akhtar said.