Conclusion
Sun bleaching your hair is an effective method of lightening your hair. You have to ensure that you do it right and be consistent with it so you can get the best result. If you want to avoid sun bleaching your hair, you should take prevent measures like using a hat when walking in the sun.
References
[1] https://en.wikipedia.org/wiki/Melanin
[2] https://www.cdc.gov/nceh/features/uv-radiation-safety/index.html#:~:text=Ultraviolet%20(UV)%20radiation%20is%20a,The%20sun
[3] https://www.mayoclinic.org/diseases-conditions/skin-cancer/symptoms-causes/syc-20377605
[4] https://www.recipevibes.com/lemon-juice-recipe/
[5] https://en.wikipedia.org/wiki/Citric_acid
[6] https://en.wikipedia.org/wiki/Scalp