System storage High

The Storage tab is known to report incorrectly. Also check by choosing your Mac HD and "Get Info" (command-i). It may be different. Try rebuilding Spotlight index.

How to rebuild the Spotlight index on your Mac - Apple Support

Some of the space may also be from Time Machine Snapshots.

About Time Machine local snapshots - Apple Support

Download Omni DiskSweeper:

https://www.omnigroup.com/more

DiskSweeper can give you a more accurate read of disk space than Finder or Storage Tab of About this Mac. It can also show you the precise size and location of all your files. It will inventory your disk starting from the files that take up the most space. If you want you can even delete files from OmniDisk Sweeper. But be careful some of the items may be important to your system.

Hey, sukhen!

Thanks for stopping by the Apple Support Communities. I understand from your post that you're concerned about the storage on your MacBook Air. I'd be happy to help!

As you use your computer, you'll add to its storage when you download and install apps, create documents and projects, import photos, save music, etc. If you'd like to free up some space on your Mac, you've got several options to do so, and can get more information in the following Apple Support articles:

How to free up storage space on your Mac - Apple Support

Optimize storage space on your Mac - Apple Support

Move your Photos library to save space on your Mac - Apple Support

Cheers!