Petrol has become cheaper by one rupee 42 paise a litre and Diesel by two rupees one paise per litre. It includes state taxes. The new prices came into effect midnight last night.Petrol will now cost 61 rupees 9 paise in Delhi, 64 rupees 97 paise in Kolkata, 65 rupees 70 paise in Mumbai and 60 rupees 65 paise in Chennai. For diesel, the consumer will have to pay 52 rupees 27 paise per litre in Delhi, 54 rupees 57 paise in Kolkata, 57 rupees 47 paise in Mumbai and 53 rupees 73 paise in Chennai. In a statement, Indian Oil Corporation said the reduction in prices of petrol and diesel has been effected following decline in prices of pertrol and diesel in international market and changes in Rupee-Dollar exchange rates.