fuel tank draining

Our Indian fuel is contaminated terribly!
Especially with rain water dirt and humidity. I bet they impedes optimum performance of our rides.

how to drain every drop of fuel (occasionally) from modern cars like Punto and put it back on track .let me guess I may find some water and sand partical sediments at bottom.

Ususally water gwts into the tank when fuel bunks have a low frequency of usage. On petrol engines it is not a big problem to have some water in the tank. However, on modern Diesel engines this is a different story. As water is heavier than Diesel, it will be likely to be some water going into the engine when present in the tank. As Diesel is an oil it does lubricate the injectors. Water that pushes the Diesel out will be detrimental for the injectors and will destroy them in a short space of time.