Nothing works 100%. How many nines does "all the pollutants" consist of? This is important because the amount of waste produced by coal is vast, many orders of magnitude more than nuclear, so even many nines can still result in more harm than from nuclear.

Also, how do you store the pollutants, and why doesn't that technique work for nuclear waste? I'm guessing that storing the pollutants consists of putting it in good, strong containers, which works fine for nuclear waste too. It's not perfect, but it doesn't really make much of a difference whether it's mercury or uranium leaking.