I had almost 10k of unwanted unread mails in my gmail inbox which I always wanted to delete. Recently I was able to do that in just one step I'm sharing you how to do deleting in one step.....
Type "is:unread" in your search mail box (one located at top of your gmail), click search mail.
Then select "All" which will only highlight the 20 or so on your page. However, once you select "all" it gives you an option of "select all conversations that match this search". click this, it highlights all unread messages, and then you can delete them all at once.
Type "is:unread" in your search mail box (one located at top of your gmail), click search mail.
Then select "All" which will only highlight the 20 or so on your page. However, once you select "all" it gives you an option of "select all conversations that match this search". click this, it highlights all unread messages, and then you can delete them all at once.