How can I find out those links are unwanted links?
- Blackhat method
- Unnatural way to get the backlinks
- Suddenly got the huge backlinks
- Authority and Trust
- Penguin algorithm said about low-quality backlinks
- Suddenly drop your keyword rank in SERP
If you want to more detail, Please read our another post: https://engage.extreme-seo.net/thread/what-is-the-meaning-of-toxic-links-in-seo/