即使碳关税的征收违反了国民待遇原则和最惠国待遇原则，碳关税还可以从GATT1994第20条例外来寻找合法性依据。
Even if carbon tariff is not consistent with the principle of national treatment or the principle of most-favoured-nation treatment , it may be also legitimate under Article XX of GATT 1994 .
最惠国待遇关税