It's called a tariff. They're an incredibly blunt tool and they're generally not a good way to make anything "fair".
Also the rarity of a skill does not necessarily correlate to its economic output. So you would reduce the supply of workers for an arbitrary number of industries where wages are not higher than that number you just pulled out of a hat.
Also the rarity of a skill does not necessarily correlate to its economic output. So you would reduce the supply of workers for an arbitrary number of industries where wages are not higher than that number you just pulled out of a hat.