Noise pollution is caused by various things. In a city traffic is one of the main causes. In a crowded environment such as a railway station or a mall people can produce amounts of noise that could be construed as being polluting, or distracting. Birds and dogs also produce it to some extent. Many causes produce noise pollution, but the one thing which connects all of them is that they are distracting.
Living on a fairly busy street in a city as I do I am constantly hearing the passing of cars, sometimes the occasional truck or bus, and motorcycles, not to mention many pedestrians. The street is close to the local shops, pubs and clubs and as such often at night you will hear many drunken youths carousing and fighting their haphazard way back home after a night of binge drinking and vandalism.
Noise pollution is thus something I have become used to. Any noise can be distracting if one allows to to be so. Something as simple as footsteps or a bird call can be immensely distracting to one who thinks a lot and is not terribly sound of mind. Any one who is high strung, intelligent or in any way emulating the methods of Holmes will find the problems of city living are immense and that concentration is vital to continuing thought chains. Everyday tasks become exceedingly difficult when one is distracted. Something as simple as making a cup of coffee often causes me to go partially insane.
When I go for my walks the only time I do not feel distracted is when I am walking through Puckey's Estate nature reserve, due to the lack of human activity there relative to other parts of the city. Whilst it is close to Squires Way and the traffic on it, the noise is somewhat lessened by the trees between the road and the walking track. Also most people choose to follow the bike path along Squires Way, thus the density of people is less at Puckey's Estate.
I used to go bush-walking in the local hills and there I would be less distracted, and it was there that I did some of my more important thinking on various things. However ironically enough one can benefit from certain types of noise for thinking. Repetitive noises are useful in creating a lack of distraction and allowing for a normalcy to develop within the brains neurone paths. Hammering, drilling, trains, even cars and telephones may produce a beneficial effect upon the thinking process if operated correctly. But usually most human activities are immensely distracting and as such one goes more insane every day.