MILTON WATER BOTTLES: Part of every schoolkids arsenal - along with a giant backpack and a lunchbox - essential for dealing with hot days at school. Given how hard the insulated shells were, they also became weapons in any fights that broke out. Somewhere around 6th standard it became really uncool to carry one around and everyone stopped.
TUITION: With the exception of a few brainiacs, after school "tuition" was part of your school day. Since most schools were "all boys" or "all girls" tuitions were where you met members of the opposite sex. Nothing like pre-puberscent romance in a crowded room full of sweaty kids trying to wrap their mind around differential equations ("maths")
DESIFICATION: I'm not sure what else to call this phenomenon, but it refers to the alteration of content in commercial properties to make them more palatable to the India consumer - for example I remember being fascinated that this particular GI Joe diver guy was actually from Goa! Also all identifiably Indian content in Phantom comics were altered - Bengali became Denkali, the Singh Brotherhood became the Singa Brotherhood etc.