Spam Mails in INBOX
I am using Yahoo Mail for a long period. You started to send many SPAM mails to my INBOX. I am not satisfied from this condition. I have to clean my inbox due to these many spam mails. This is lost of time for me.

Sometimes when a flood of junk email comes into a mailbox suddenly, it could mean that a hacker is trying to compromise the account. In this Spam distraction tactic, they send tons of junk to the mailbox in order to distract the user while they try to use the account for their purposes.
For these situations, I would reset the password and make sure the account is secure. Mark the Spam emails as such as much as possible as well. Another option, if needed, is to deactivate the account temporarily (for 1 or 2 days) and then reactivate it to see if that will help stop the spam. Emails sent to a deactivated account will typically bounce back to the sender.