Well you got it wrong.
Currently the ration card system we have is you buy your subsidized stuff (food, fuel) at govt stores and govt pays the trader. Huge chance of fraud and corruption.
What adhar allows is even poor to have an unique identity (UID) verified by the govt. This very improtnantly enables them to get a bank account linked to your UID which is impossible today for the nomads and the below poverty line people since they don't have passports or driving licenses.
The next stage of the process is that the poor now buy their food on open market and govt directly deposits all the subsidies available diectly to their adhar linked bank account. All the middle men are trashed and window of corruption is a LOT less. Also there is electronic paper trail should a fraud occur. And yes there will be fraud since nothing in the world is full proof and completely secure. But its leps and bounds better than what is going on today.