What is FASTag and Why is it compulsory?

FASTag is a device for making toll-payment directly from the prepaid account. It uses Radio frequency Identification (RFID)

What is FASTag and Why is it compulsory?
What is FASTag and Why is it compulsory?

FASTag is a device for making toll-payment directly from the prepaid account. It uses frequency Identification (RFID). Fastag will be mandatory on all four wheelers passing through the national highway from december 1,2019.
About RFID 
Its full form is Radio-Frequency Identification and it uses radio waves to read and capture information stored on a tag attached to an object. This tag can be read from up to several feet away and does not need to be within direct line-of-sight of the reader to be tracked. It is applied for tracking items or as a pass. 
How does it work?
The vehicle's windscreen is Fastaged and it has RFID installed in it. As soon as your vehicle comes near the tool plaza, the sensor on the tool plaza cuts off the charge on that tool plaza from your Fastrack account as soon as you come in contact with the fASTag installed in the windscreen of your vehicle and you need not stop there for paying your plaza tax. This tag installed in the vehicle will start its work as soon as your prepaid account is activated. If your FASTaged account exhausts you need to recharge it for further use.
Validity
It will have validity of Five years and after five years you need to install a new FASTag on your car.
Why in news? 
Centre is making FASTag compulsory for all commercial vehicles -- trucks, taxis and buses.