Nausicaä of the Valley of the Wind(1982)

Kaze no Tani no Nausicaä

Humanity, in its hubris, has precipitated a devastating environmental disaster. Flourishing industrial civilizations have been swallowed up by the Sea of Corruption, an enormous forest of fungi releases a miasma of poisonous spores into the air. Nausicaa, a compassionate young princess, and her allies battle to heal a wounded world and its inhabitants...

(Source: Viz Media)

Note: Won the 26th Seiun Award for Best Comic (1995).