It is kinda annoying when you drive over the speed bump! The squeaking sound get worse when it is wet. Tried to locate what is the possible caused by spraying WD40 to all the bushings. Finally I found out the anti roll bar bushing that were causing the squeaking noise.
You can see the inner sides of bushing still ok only the outer were worn out.
VW Polo 1.2 TSI anti roll bar size is 16mm in diameter. After changed out to the new one. No more squeaking noise.