We collected anonymous data on 100,000 websites and 450 million pages using the SEMrush Site Audit tool to determine the most common on-site technical and SEO mistakes and issues. Every issue has a severity level from 1 to 5, where 5 is the highest level of severity. Below you can see the percentage of the sample websites that face certain types of issues.
![The 40 Worst SEO Nightmares #Infographic #SEO The 40 Worst SEO Nightmares](https://i.imgur.com/JLPt80e.jpg)
Infographic by: www.semrush.com
![The 40 Worst SEO Nightmares #Infographic #SEO The 40 Worst SEO Nightmares](https://i.imgur.com/JLPt80e.jpg)
Infographic by: www.semrush.com