The first challenge is the definition. It's always an issue.
We have to give you an idea of the range of what we're dealing with. On the one hand, you have the IEA, which has estimated that overall global subsidies are in the area of around $450 billion and are all related to consumption. Iran pays way lower prices for their fuel than the global market. They don't really look at their production side at all.
On the other side and on the other extreme, you have the IMF, the International Monetary Fund, which takes into account the entire social cost of carbon. They estimate the subsidies to be $4.5 trillion. The UNDP, OECD, IEA and all of these multilateral institutions are trying to get to some kind of common understanding of what “subsidy” actually covers—let alone “efficient” and “inefficient”. Finance Canada, to be absolutely frank, still has not been entirely transparent about how it addresses subsidies.
I'll leave it at that.