Two reasons why hydrogen is not commonly used as a fuel

The problem is that hydrogen is more expensive per energy unit, and difficult to store. And it has to be generated with electricity, which is mostly generated using fossil fuels.

Reason why hydrogen is not commonly used as fuel are

Explanation:

hydrogen requires a large fuel tank for storage as it occupy more volume. hydrogen is not readily available in the atmosphere. It requires processes like electrolysis and steam reforming for production.