Coolant / Coolant

Hello in the round, Today I have refilled wiping water and I noticed that cooling liquid is slightly yellowish. I can swear that as far as I could remember it was dark. No, am not color-blind or drunk! and nothing was changed either. Ask you: what can be the cause of change of color? berlingo 1889/AAH 130 HP Diesel Built 2021 Motor DV5RC