噪音污染
Noise pollution which encompasses roadway noise, aircraft noise, industrial noise as well as high-intensity sonar. The noise for Karachi came to 80 dB (A), the General Noise Index x (G.N.I.) to 460, and the noise pollution level (N.P.L.) to 99 dB (A). These values are significantly higher (P less than 0.01) than the available international data. The sources of noise production were identified as, the road traffic, human activity, industrial and civil works, mechanical and engineering workshops. The most noticeable sources of noise pollution in Karachi, are the autorickshaws, trail motor bikes and the fag horns of public transport. The noise emanating from a wide variety of sources such as; Motorcycles, Auto-Rikshaws, Cars, Wagons, Mini-buses &amp; Buses, Trucks, Tractors, Water tankers, Bulldozers and Machine drills etc.