Hello,
Wont recommend
1. Honda Civic with CNG Can face in substantial ground clearance issue especially if car is fully occupied
2. Model is discontinued Long Back making Spare Parts expensive
3. Fitting CNG in Automatic Car is not much successful
Only if getting a throw away price say under rs 2 Lakh and service history verified with car thoroughly inspected by a mechanic / Honda Service center without any suspension issues, Performance issue due to CNG in Automatic - then only consider buying same.
Hope should help !!