Stop this childish talk and leave the "CNG hi lagwani thi to Mehran lay letay" wali sooch... Shayad aap kay liye Reborn koe bohat bari balla hai k uss mai agar CNG laga di to koe bohat bara gunnah ho jai ga. Come on! Reborn is an ordinary car and CNG is an ordinary fuel. I don't know which extraordinary Reborn you drive that gives you 18km/L.
The point is, there is no harm in driving a Reborn on CNG. Reborn hai, jahaaz nahi hai. I'll give you very good performance and consumption. Yes, you should avoid CNG in Prosmatecs because of other reasons. Its not about affordability at all.