The price of petrol and diesel will increase from midnight on Tuesday. The price of both grades of petrol would increase by 17c a litre and diesel by 10.12c a litre, the energy department said yesterday. “The fuel price changes include the annual margins adjustment, changes in the basic fuel price and the decrease in the slate levy,” it said in a statement. The annual adjustment to the petrol margins had increased and this had affected the petrol price, the department said. “The decrease in prices of the international petroleum products was not substantial enough to offset the effect of the volatile exchange rate on the fuel price,” it said. The wholesale price of illuminating paraffin would increase by 16.50c a litre. The single maximum national retail price would increase by 22c a litre for illuminating paraffin. The maximum retail price for LP Gas would increase by 18c a kilogram.