honda city is such a fuel efficient car on stock tyres its not even funny. why in the world would any one covert it to CNG. it already has a weak engine, putting it on CNG would make matters worse. The real average of the car kicks in after 5000KM, which i am currently experiencing. My cars average is improving with every refill. its a shame that people convert their vehicles on CNG on just 1000KM of running claiming the car isnt giving good fuel average...let the engine have its complete running then decide !!!..if you drive an auto, dont push the accelerator too hard, otherwise it will consume more fuel...gradually accelerate.