It isn't. In fact, it's the cause of so many of them, I don't even know where to begin.
How is Christianity a remedy for all ills in modern world?
I don't know that it is, if you look at it, religion in general is the basis for a lot of the "ills" in the world.
Because the Bible tells us that there is nothing new under the sun and that all scriptures are inspired of God. For teaching, reproving and setting matters straight. (Ecclesiastes 1:9) (2 Timothy 3:16)