Russia say that it's Ukraine refusing to demine the waters that it, Ukraine, mined in the first place. I've also read that the impact of the (lack of) grain exports is drastically overblown
Well, those ports would not have been mined if it weren't for the Russian invasion. Without Russian ships roaming the coast and ready to attack or disembark soldiers and tanks the situation would come back to normal ASAP.
Anyway that's not the problem.
The grain shortage is not about an insufficient amount of grain worldwide, but because of less grain available on the markets prices went up and many poor countries cannot compete and/or afford to buy it at current prices. Also because those who can afford it are hoarding since well, you may never know.
Russia say that it's Ukraine refusing to demine the waters that it, Ukraine, mined in the first place. I've also read that the impact of the (lack of) grain exports is drastically overblown