MacBook Air m3 Plastic edge below screen turning white

Are you sure it is not dirt or some sort of residue? I see some whitish stuff below the bezel as well along the gap between the bezel & rubber gasket. The latter is not scratched paint.

FYI, I've never seen the black paint on the Bezel marred. The black paint is usually on the back of the Bezel strip. I just tested scraping the top edge of a Bezel I pulled off a damaged display for an Intel Mac.....there is no paint on the edge or front. It is on the back of the Bezel itself.

If the white area was not there previously, then it is most likely some sort of dirt or residue.

a_logan wrote:

I have tried to clean it a lot using wet microfiber cloth but still no effect if it's a residue of some sort then it's really stuck there and I don't remember using something like that near my laptop at least not today. But still I will try to clean it with some dilute isopropyl alcohol tomorrow if that doesn't work guess it's staying there.

Be very careful with liquids there since they can seep beneath the Bezel & destroy the Bezel adhesive and/or leak behind the glass and cause permanent visual anomalies. Avoid using liquids near the edge of the glass including the Bezel strip.

Have you changed macOS in any way which would have affected the background near that location? If so, maybe it has always been there and only became noticeable once the background/windows there changed their look/color.

While it may be annoying to see it, you should try to ignore it.

You can take it to an Apple Store to be evaluated to see what they have to say about it.