Petrol and diesel prices were slashed by Rs 2 per litre on Wednesday, following a sharp fall in global oil prices.Earlier, petrol and diesel prices were increased in Delhi after the state government decided to increase VAT (value added tax) rate on the two fuels with effect from Thursday.However after the subsequent revision, petrol in Delhi will be dearer by 28 paise while diesel will be cheaper by 50 paise.Global oil prices have fallen below the $60 level for the first time since April on concerns over China slowdown and oversupply.Last Monday, oil prices fell nearly 8 per cent - its biggest selloff in 5 months - after Greece had rejected the bailout terms in a referendum.The recent Iran nuclear deal could also pressure on oil prices. A milestone nuclear deal reached on Tuesday between six world powers and Iran will mean sanctions that have limited sales of Iranian oil for several years are likely to be lifted in early 2016. Oil minister Dharmendra Pradhan said Iran's eventual return to international oil markets would lead to lower prices.India imports close to 80 per cent of its oil requirement. Besides global oil prices, the value of rupee is a key determiner of domestic petrol and diesel prices. The rupee has remained stable despite the turmoil earlier in global markets due to the Greece crisis.Petrol prices were last cut on June 30 by 31 paise per litre and diesel by 71 paise a litre in line with a fall in international oil rates.Oil firms review the prices of petrol and diesel every fortnight. On Tuesday, Brent crude was trading at $57 levels.