Is pre-school necessary for kids? If yes, how?

if you mean nursery and kg, then yes, unfortunately in India our schools barely give admission to kids who have not done the same through a formal place. however, if you are talking about a playschool then it is not necessary at all. you can check with schools around your area as honestly, it is very easy to teach kids most of the basics at home through fun and play methods. check if they accept kids straight in grade I and then you can skip preschool :)