Tribune News NetworkDohaQatar Petroleum has reduced prices for super and premium grade petrol for March.Premium grade pertrol will now cost QR1.60 per litre as opposed to QR1.75 in February. Super retails at QR1.65 a litre. It was QR1.85 in February.At QR1.70 per litre, diesel is cheaper by 20 dirhams in March.