Why are my bike brakes squealing and how can I fix them?

Your bike brakes may be squealing due to dirt or debris on the brake pads or rims, misalignment of the brake pads, or worn brake pads. To fix this issue, you can try cleaning the brake pads and rims, adjusting the alignment of the brake pads, or replacing the brake pads if they are worn out. If the problem persists, it may be best to consult a professional bike mechanic for further assistance.