Yogi's Gang S01 E11 Mr. Smog

The gang stops at "Smog City," a city covered in smog by Mr. Smokestack Smog's smog factory, where he has convinced everybody that smog is good for them. He encounters Magilla Gorilla, Peter Potamus and Snagglepuss (who are looking for bananas for the ark) and tries to convince them into his way of thinking.