For Example: My Car registration is of Delhi and if I shift from Delhi to Banglore or any other city then what will be the procedure for transfer. As far I know is that I have to take NOC from the city where car is registered. Do I need to pay road tax and register again my car number in the state where I am going?
Yes, You need to get your register afresh in the new state. You'll be issued a new number for your car. In my opinion, NOC is just to ensure that there is no criminal history or alike any objection for this registration. By this way, they also track the car registered in new state in the old state's transport records.
If you are going to stay less than one year then you need to pay the Road tax and if the car less than a year old then entry tax also. Registration is required if more than one year of stay is expected.