Following a further cut in petrol price, the gap with that of the CNG price has shrunk to less than 20 percent. Petrol-CNG price difference has shrunk to Rs8.21 or 17 percent after the government last night reduced the petrol price from Rs57.66 to Rs56.21 per litre in pursuance of the directive of the Supreme Court. Reduction in per litre petrol rice since last October cumulatively by about 30 percent has triggered a falling trend in CNG sale. While CNG dealers in a bid to keep their sales stable seen offering CNG even at a discount at different places of the country.