Oil marketing firms have today once again slashed prices of petrol and diesel across the country. This is the 5th straight day when OMCs have slashed fuel prices. In Delhi, petrol is being sold at Rs 77.56 whereas diesel is available at Rs 72.31 per litre. Yesterday, petrol and diesel were retailing for Rs 77.89 and Rs 72.58 per litre respectively in the national capital.