A similar law was passed in Venezuela in ~2005. It forced radio stations to play traditional Venezuelan music as a percent of all their airtime.
From the only article I could find in english [0]:
> The law can make listening to the radio an adventure in dizzying contrasts. One minute a disc jockey is playing American rap, and the next minute it’s flutes and fiddles from the Andean highlands.
It pushed some local artist to get creative and come out with some electronic traditional music, which frakly, sucked.
Oh, and radio stations worked around the required quota by playing the mandated music very late at night.