There are many ways to manage and organize the mail you receive in Gmail. I keep organized in my mail by using Filters. Using Filters, I never have to see those unwanted emails. A new way to organize your mail is to BLOCK those unwanted emails.
Open a message from the person you want to BLOCK, hit the down arrow in the upper right and then tap BLOCK. The future emails from that person will head straight to the spam folder. Never see it again. If in the future you decide you want to see those BLOCKED emails, you can unblock the person in the Gmail settings.
This is a new feature to Gmail and it will also be rolling out later this week on Android. So check it out and stop seeing all that unwanted email.