How do I optimise System Storage data on my MacBook Air?

”System Data” is not data created by the system.

“System Data” is data that Spotlight could not categorize as one of the other bins. Sometimes, it is just Spotlight failing to correctly identify the data. In your case, it is the runaway cache for the Telegram app.

OP wrote " I tried CleanMyMac and found that there is a mind blowing cache datas occupied by telegram would like to know is this necessary or how to overcome this issue."

Part 1 of 2

Once you’ve installed and integrated this software " CleanMyMac " Aka " BrickMyMac " into your computer, you’ll need to start from scratch. 

It can be a bit of a hassle, as you’ll need to spend hours or even days searching for all the necessary files and programs. However, it’s effective in removing the AV software.

For Apple Silicon computers, use Disk Utility to erase a Mac with Apple silicon. For Apple Intel computers, use Disk Utility to erase an Intel-based Mac and then follow the instructions in How to reinstall macOS.

Before proceeding, make sure to create a Time Machine backup. If you decide to go this route, I suggest not using Startup Assist to migrate everything back. This might inadvertently introduce ( CleanMyMac back into the operating system. 

Part 2 of 2

CleanMyMac , aka “ BrickMyMac “

To put the CleanMyMac in context and the damages it may have or has already done.

This application can or will Muck Up your User Account ( Home Folder ) of this machine.

It does not touch the Operating System itself unless you consider your User Account ( Home Folder ) as part of the Operating System

Then in that specific context - it has Mucked Up the Operating  System 

In which case, the Operating System is hosed 

You can use a tool like GrandPerspective to try to find large chunks of data, but it may not be all in the same place.

How long has it been since you deleted the cache? An SSD can take a day to restore the storage locations to writeable.

koushikromel wrote:

I'm sorry that I can't understand few things here!

You are telling about this cleanmymac software that I should completely remove from my Mac or what?

No, it does not mean remove the CleanMyMac Application itself .

It means exactly would it says.

Reformat the drive as per appropriate method " Intel " OR " Apple Silicon Computer "

That is Starting Over from Scratch

And it is hard for me to again format and reinstall my Mac since I have some files that I need also I couldn't backup anywhere at this moment also for Time Machine I don't have any hard drives.

Lesson Learned the hard way unfortunately

If you have used or are using Time Machine Backup Utility  you maybe able to Restore the Deleted Files 

For future purposes

To truly protect your non replaceable Data

Have a 3-2-1 Rescue Plan in place and always current

3 Backups using 2 methods and 1 off site incase of natural disaster or un-natural disaster.

Each of the above should be done to a Dedicated Single Purposed External Drive 

Below link is intended to augment what TM Backup does 

https://bombich.com