KARACHI, Feb 14: Pakistan observed the World Noise Day on Friday with considerable majority of its urban population exposed to exceeding levels of noise pollution.

Patients at hospitals, as well as students at schools and inhabitant of residential blocks, are equally exposed to noise- induced trauma round-the-clock in Karachi.

Noise caused by motor vehicles is the main cause of inconvenience followed by that of noise emitted by many of the commercial units, unchecked use of loud-speakers and also indiscreet exposure of workers besides people living in close vicinity of certain industrial units.

Despite passage of 10 years, the National Environmental Quality Standard (NEQS) for Noise Levels, with particular reference to motor vehicle-induced noise remains to be efficiently implemented across the country.

While the NEQS for motor vehicle noise indicates 85 decibels as the maximum permissible noise emission up to a distance of 7.5 metres by any kind of vehicle, a study conducted by the Institute of Environmental Studies of Karachi University identified emission from rickshaws to be in the range of 93 to 104 decibels.

Auto-rickshaws in Karachi are a major source of noise pollution. The data available with reference to comparative recent levels of noise pollution in 23 different sites in Karachi mentions that auto-rickshaws contribute to 63 per cent of noise, followed by 24 per cent contributed by buses and 13 per cent by other vehicles, including cycle rickshaws, cars and soforth.

According to International Occupational Safety and Health Standards hearing loss is most likely risk when a person is exposed to 115 decibels noise for more than 15 minutes. Eightyfive to 90 decibels for eight hours a day is stated to be the maximum allowable occupational exposure.

Another study conducted again in Karachi by the PCSIR shows that usual vehicular traffic within five metre radius of M. A. Jinnah Road and Jehangir Road generates a median noise level of 84.4 decibels which decreases at more distance.—APP