looking for an institute to train my son
Don't put him anywhere! The first teacher should be the father or mother. The basics of playing chess your son can already learn when he's 4 or 5 years old. The most crucial thing of playing chess for a child is having fun. If your son is disappointed, he'll be unlucky and stop playing, so he won't ever become a tournament player.
When he understands the basics, then you should look for a club or something else in your region, so he gets a good guidance. Pitty, you're from India and not from Belgium. I'm a chess coach for kids and adults in a club.
I agree with Chibar, if he is really young like 5 or 6 years old the best is to teach them your self, make him smile, make chess fun for him, you dont need to have 2000 elo fide for that, just have good humor, make him love chess, thats the most important thing, there are a lot of chess schools that they teach chess good yes but they dont make the kids love chess