My car is giving me 155-160 Kms on a full cylinder (55 kg) with A/C, within city.
I installed CNG on my City 98 about five months back. The car was doing b/w 130-140 Kms on a full cylinder. Then with A/C it was doing about 120 Kms. About 2 weeks back I changed the Air Filter, the fuel filter and asked the mechanic to adjust the timing. Since then I am getting that 155-160 Km avg, that is quite exceptional.