none of the cars in pakistan had engines designed to be used on cng.
i have had a cng charade and a cng cuore, both well maintained and driven to high mileage. cuore was at 100,000 km when sold, charade was at 250,000 km when sold.
CNG is trouble some. always some issue popping up. it runs much hotter then a petrol engine, valve seals wear out faster. engine wears out faster.
i currently have a civic 1996, petrol from the start. driven 230,000 km now. after driving a petrol only vehicle, i will never every go back to cng.