Thank you very much for the question. There are various definitions, but an example of an inefficient fossil fuel subsidy would be one that would encourage the production of fossil fuels. You'll see, for example, that one of the subsidies that have been eliminated is around the tax advantage for production of oil from the oil sands.
An example of something that is not considered inefficient, and it is sort of contemplated in the G20 context, is subsidies that support remote, perhaps economically disadvantaged communities so they have an energy source to heat their homes. You do see programs like that, which, by some definitions, could be considered an inefficient fossil fuel subsidy, but it's contemplated under the G20 rules that this sort of thing would not count.
Those are just a couple of examples.