Two examples of light pollution, at about 6 pm-ish. The first is an orange glow in the sky caused by sodium street lighting in Ipswich reflected off low level cloud. The second is a bright light to the rear of a house just across the field, which is on most evenings.
They're both reasons why it's become much more difficult to see the stars at night. Light pollution is also very wasteful of energy. The Campaign for Dark (star-filled) Skies wants action to prevent light pollution, and so do I.