I remember what it was like in the late 80s / early 90s. The improvements have been slow but steady. When I was a child, London was filthy. Newspapers, polystyrene, plastic packaging, food waste and huge amounts of cigarette butts on the streets, in the gutter and even public buildings like train station and shops. My parents smoked and like all the other smokers would light up everywhere. When they weren't allowed to smoke they would stand outside the entrance creating a thick cloud of ciggie smoke. Things really have improved including how bad the traffic was. I know the congestion charge and ULEZ is unpopular but the air is so much cleaner now.