Helium is the gas commonly used to inflate balloons. This non-toxic, colorless, and odorless gas is lighter than air, allowing balloons filled with helium to float. Helium is a noble gas and is safe for use in balloons, making it a preferred choice over other gases like hydrogen, which is flammable. Helium-filled balloons are commonly used for celebrations, events, and decorations, providing a fun and festive atmosphere. However, helium is a finite resource, leading to ongoing discussions about responsible sourcing and usage.