Inappropriate Downloading Notification. How to remove? I had installed a Hindi Dictionary Application which contains the Speech to Text Output.After pressing the speech button then the Downloading notification came up,three days passed still the notification isn't cleared any way to handle it.Please Check Image Here
You need to clear the data and cache of the app:

The steps depend on phone make and Android version:

Touch and hold the notification > Touch the 'i', it will bring you to the app (Downloader Manager) > Clear Data and Cache and you're done.

On Samsung J5, Marshmallow (6.0.1)


Touching an app notification: 

Touching the i symbol:

Touching Storage option: