Old ICloud account is popping up in my iPad and I deleted my old email

Apple ID accounts never die; they exist forever. Even if the email address changes, the account remains. And purchases made with an Apple account remain with that account forever. So you will have to delete all content purchased or downloaded with that account, and re-purchase it. Or recover the account and use it.

Note also that, while the Apple ID is an email address, it is also a user ID. If you have the password you can still use the old email address to log in to https://appleid.apple.com to change the email address. If you have trouble with that you can contact Apple's Account Security Team by following this link: Apple ID: Contacting Apple for help with Apple ID account security or by calling and asking for help with account security: Apple phone contacts

You need access to that e-mail to change to it.