I am not from India so I can't help you. So we talk of retail material shops.
Boxes should have seals that prove they are originan and brand new.
Inside you should find warranty certificate.
If they are fake products, the box won't have inside what's inside original box (that you can check online.. on Google images or reviews on good sites.)
Many products should also have a registration code, you register the code on the brand's site.. and so you know if it's a fake or real.