In the context of proposals to the use of hydrogen-enriched CNG (H-CNG) as fuel for buses in public transport, consider the following statements :
- The main advantage of the use of H-CNG is the elimination of carbon monoxide emissions.
- H-CNG as fuel reduces carbon dioxide and hydrocarbon emissions.
- Hydrogen up to one-fifth by volume can be blended with CNG as fuel for buses.
- H-CNG makes the fuel less expensive than CNG.
Which of the statements given above is/are correct?