Not all users can distinguish between colours. Colour alone should not be relied upon to indicate key information such as links, chart information or selection options. Your user may be
Avoid using colour on its own to convey information on its own.
"...available options are green"
"required fields are marked in red"
A user may have an impairment that prevents them from perceiving the correct colour, our could be use a screen reader which will not register the colour information at all.
Provide additional text or other distinction along with the colour.
"...available options indicated by the green tick"
"required fields are marked with a red asterix"
If you have images that are dependent on colour such as a graph or heat map, consider including a hatched key or additional labels.