You can have fun and decorate for parties to reduce your impact on the environment, as there are plenty of options to provide an eco alternative to balloons.
A sustainable alternative to balloons for decoration is paper chains. Make a room bright and festive by making long chains, and hanging them in garlands.
Trying to create a ‘surprise’ moment, confetti is a good alternative to balloons. Just be sure to find biodegradable, non-plastic confetti, preferably made from natural materials.
Another alternative room decoration to balloons, is to make bunting or garlands. Something that will be long-lasting but takes a bit more time, sew cloth shapes across a piece of ribbon or string.