I watched this sometime between 1970 and 1974. Saw it in Black and white (however my parents didn't have a colour set back then so it may well have been shown in colour)
Two spacemen have landed on some planet where all live in giant towers. The elite on top floors and more crowded the lower you get until basement levels are almost shoulder to shoulder.
Outside and between the towers is generations of garbage under a fierce sun, this has caused vermin and small animals to mutate into giants. Some of the high level tower people are discussing a recent 'safari' to the outside they made for big game hunting. Hence the phrase one used "never go after a wounded mouse"
I think the two spacemen cause some kind of social unrest by getting some lower people into the top tower levels "look at all these cubic feet of living space they have up here"
At the end they are back in their spacecraft getting ready for launch in a very heavy rainstorm, the view moves back and a giant terrier dog is in actuality urinating onto their rocket amidst piles of rubbish.
Not sure if this was a one-off or a series, thanks.