Regarding MAIL with gmail account

I have added my gmail account to MAIL option lately I notice that though I have no unread messages the All mail option still shows me unread messages.

I have tried all options such as downloading the Gmail APP and syncing without delay, deleting and reseting the account to no avail it still shows me messages unread when I select the unread mail option it shows me none.

Is this a problem with syncing with gmail ? I cant find any option to sync in the MAIL section. Below topics do not provide the option of MAIL.