You have to answer this question writing about your community - but I can give you an example. Let's say your city has a problem with pollution. Let's say that the pollution is made worse because the city is placed in a valley, as many cities are (say for example Mexico City). It affects the people living in the city, their health and well-being (this would be for example the small scale) but also it affects the vegetation and quality of soil in the whole city (this could be a large scale)
