Bro, agar aapko fuel efficient car chaheye, then Swift Automatic ki taraf matt jyein. Its gas guzzler.
I do not think that it would be a wise idea to install CNG in Swift! May be other issues aa jyein, if you install CNG in Swift.
In market, many fuel efficient cars are there; Passo, Boon, Mirage, Vitz, etc. You can choose between these vehicles and appko CNG ki b zarurat nai paray gee.