Looks like you had some app which used huge amount of data in the background but you probably have deleted the app already. So no need to worry.. it won't come in next month's report. If you remember which app you uninstalled this month or recently it might help to narrow down the culprit app/apps
Bro, that's used data of previously installed apps or games, so that's leftover data and do its always recommended to clear data before uninstalling any apps(its not the perfect solution, but definitely help upto some extent)..Now, relax, no need to panic..
If still you want to remove it, you are left with two options, take backup of your device and factory reset it and second use some 3rd party apps to completely clean such unwanted files...
Please don’t call me Sir, Sid is fine..aapne recently kuch installed kiye hoge ya pehle bhi..ab delete hone k baad woh apps nahi pata chalege..ye bas unk leftover data used hai..
