Petrol prices were reduced again for a second time this month. In Delhi petrol will cost less by 2.46 per litre at 67.78 with effect from midnight tonight. While in Mumbai the prices of petrol will come down by 3.10 paise to 73.35. In Kolkata petrol will cost 3.07 less at 72.74 per litre. In Chennai, petrol will cost 3.13 paise at 72.27. State-owned oil firms, which had last month hiked petrol price by 7.54 a litre, had on June 3 cut rates by 2.02 per litre.