Religion has been a part and parcel of life and of course it has been very integral to life. Man from time immemorial has some sort of attachment to religion or to put in another way man has always been in a religion. One of the aspects of religion is belief in a certain God or deity and also the belief that there are some supernatural entities. It is a kind of belief that man has another identity, that is his soul and to discover his soul is what religions teach in the world.
The question whether religion is necessary is hard to answer. Religion relates that man is controlled by his destiny and what he does has to do with the wish of some divinity. Different religions have different views about life. Christianity believe in free will. That means man is free choose between good and bad.
In fact religion has kept humanity in harmony. Books of religions all over the world tell something about morality and ethics. Of course religions keep people from committing sins and particularly the fear of hell also keep people from doing sinful deeds. In the mean time we know that people from Christian countries engage in charitable jobs and they help large numbers of poor and destitute all over the world. However at times when religions become politically driven. Yes sometimes people in the name of religions behave inhumanely also and we know a very big example of Hitler who was going against Jews and wanted to make the world totally free of Jews.
Yes, there are good aspects of religions and we can learn them and apply in life and not the political aspect of it like the extremists Hindus who want to dominate the rest of other religions in Nepal and India. By religion we must understand charity, kindness, humanity and the like and only making temples and worshipping particular Gurus or doing some rituals are not religious acts. They are rituals and one cannot be religious by acting ritually believing in so many Gods and performing religious duties. Of course all of our objective as regards being religious is to save the planet earth and to serve humanity.