Need suggestion for 1000+ service pages using same content.

Need suggestion.Okay so I recently did some work on a website which included off-page SEO, Now the person wants me to manage complete SEO.

But I saw his site has almost 1000 location based service pages for some reason providing same services [ "service" + "Town Name" ] targeted in a single Country. Using exact same content on all 1000 + pages.

I have explained him how it can harm the website's Performance and asked him to create a Separate Landing Page and I have Added a canonical link element to all duplicate pages.

What should I do further with those duplicate pages..?