In India the government is very chaotic and poorly run. They are forced into action by public pressure. When it's a larger event, there's a lot more pressure - to do something, to investigate, to give some kind of compensation to the victims. With the smaller attacks, the pain is concentrated on those affected, because they've not just been forgotten by everyone else, which is normal, they've also been forgotten by the government, which lets the cases drag on for years in the courts.