In my experience the big PSO Company Operated petrol pump in Cavalry on the way to Defence.
The Petrol filled from there acutally FEELS different while driving the vehicle.
Then again, all the Army and most of the Govt vehicles are filled up from this station at night from 11:00 to 12:00 pm and it is closed for the general public during these timings. I hardly think that the Army would accept substandard petrol from a PSO company operated petrol pump. This IS the best place to get quality petrol and in the right quantity.