The mixing of hydrogen with CNG provides a blended gas termed as H-CNG. It stands for hydrogen enriched compressed natural gas and it has the benefits of both hydrogen and methane. It's a combination of compressed natural gas and few percent hydrogen by energy.

It is used as a fuel in an internal combustion engine and also for home appliances. As compared to conventional CNG,  the use of H-CNG may reduce the emission of carbon monoxide gas (CO) up to 70%, besides enabling up to 5% savings in fuel.

In a move towards wider adoption of other clean fuel for transportation, the Ministry of Road Transport and Highways on Monday allowed the use of Hydrogen-enriched compressed natural gas.
The ministry has been notifying various other clean fuels for transportation. The Bureau of Indian Standards (BIS) has also developed features of H-CNG as a fuel for automotive functions. Some CNG engines were tested to know about the emission reduction using H-CNG as compared to ‘neat’ CNG.

It is an intermediate but major step in our transition towards a hydrogen economy. The most promising fact of this technology is that it'll provide the utilization of the existing infrastructure of CNG buses as well as the piping network and dispensing stations. Thus, it can be seen as the next-gen CNG for cleaner air, it said in a report in 2018. ARAI (Automotive Research Association of India) and IOCL (Indian Oil Corp. Ltd) have dispensed tests on 6 CNG heavy duty engines using H-CNG and has found that the engine has passed the endurance tests had performance improvement which no visible issue was found in the workings of the engine.