Certain public funding sources (nih in the us) require publications be accessible to the public. https://publicaccess.nih.gov/ https://publicaccess.nih.gov/ S

Certain public funding sources (nih in the us) require publications be accessible to the public. https://publicaccess.nih.gov/ https://publicaccess.nih.gov/ Some journals like to issue a “surcharge” for this so some of the cost is passed on to the authors. Eg: https://www.elsevier.com/open-access/agreements/elsevier-nih-policy-statement https://www.elsevier.com/open-access/agreements/elsevier-nih...