Multiple path aliases based on taxonomy term I have taxonomy terms from A-Z and each article can belong to multiple terms.

for an example, when I create a new article, I have a multi select list for terms. Therefore a particular node should work for multiple URLs.

example.com/categories/a/planning 
example.com/categories/g/planning 
example.com/categories/s/planning

Please let me know if this can be achieved using a contributed module or can it be built with a custom module?
You can use pathauto module.
After installing the pathauto module, please configure the path of article content type from here admin/config/search/path/patterns.

Note: 
To use pattern require token module. Then use like following pattern:

categories/[node:field-token-of-term-reference-field]/[node:title]