CNG car owners should definitely know this. Your CNG tank needs to be tested and cleaned every 3 years, if you fail to do this, you won’t be able to get a refill. Open your gas fuel door and check for the testing date. You need to get your CNG tank checked before the test due date. The process is very simple, you just need to visit your nearest government authorised centre and pay ₹2000 to get your tank cleaned and checked. This will also help you get great mileage on your car. For more such tip