^ to add my 2 cents,
Ive said it before also a car giving 120kms on Cng is the maximum it gives, a car driven on first and second gear mostly (the homes grocery car) it hardly gives 80-100kms/cylinder. further more, IMF policies, and agreements Pakistan say all fuel prices to be almost same at some point in time.
CNG does save but for people like my dad whoose Baleno reaches a daily CNG average of around 135 kms with ac per cylinder, CNG costs him around 350-375 and petrol about 500 daily, which means daily saving worth 150, monthly saving 150*25=3750, and a yearly 330*150= 49,500. That is huge saving even if we count a straight 20k extra maintainence
But for someone who ends up paying almost similar amounds on Cng/and petrol fuel its simply no use, even if u save some thing the costs go into
premature,
oil change, battery change