The probability of that is really low though, theres not a lot of area with dense population when looking at the whole earth. And for your redirection to work, you would need really precise trajectory predictions while still very far away so a small impulse is enough.
>>echoan+(OP)
A couple of nukes missile will be more than enough to fragment it and split the trajectory to less denser population. But just like Leonardo movie look up, nothing will be done as everyone will just quarrel for attention and inaction.