Poupelle of Chimney Town (2022) on Netflix

A factory town is covered by chimney smoke, and as the townspeople haven't see the sky in centuries, they no longer believe that stars exist. A chimney sweep and a friendly monster named Poupelle decide to prove that stars are real.

There is a town surrounded by a wall that stands 4,000 meters tall. Because the town is full of chimneys, the air is always full of smoke. No one in the town knows what the sky looks like. On one night of the town's Halloween festival, a deliveryman accidentally drops the heart he is supposed to deliver. He cannot find the heart in the smoke and gives up. The heart continues to beat where it fell in the town of chimneys.

—MyAnimeList

Poupelle of Chimney Town is the story of young Lubicchi living among the thick smoke from the chimneys of his isolated town, yearning to see the "stars" - to know the truth - his father always told him about. One Halloween night he meets Poupelle, a man made of garbage, and together they look to the sky as their adventure begins. Spectacularly beautiful, filled with inspiring performances and splendid music and sound effects, and produced at Tokyo's famed STUDIO4ºC, Poupelle of Chimney Town brings laughter, tears and joy.