The minimun level of accessibility standards outlined by the Web Content Accessibility Guidelines (WCAG) 2.0. This level includes basic accessibility features that are essential for individuals with disabilities to access digital content, such as providing alternative text for images, ensuring sufficient color contrast for text, and using semantic HTML to structure content. 

 Level AA includes additional accessibility features that are designed to further enhance the usability of websites and digital content for individuals with disabilities. By implementing Level AA accessibility requirements, web designers and developers can ensure that their websites and digital content are more accessible to individuals with disabilities, including those with visual, auditory, and cognitive impairments.

Level AAA is intended to provide the highest level of accessibility and to make digital content available to the widest possible audience, including individuals with disabilities.The Level AAA guidelines are more advanced and complex than those at the lower levels, and may be more difficult to implement.