What is difference between Cognizable and non-cognizable offences?

Cognizable offences are serious crimes where the police can register a case (FIR), investigate, and even arrest someone without needing permission from a magistrate. Examples are murder, robbery, etc.

Non-cognizable offences are less serious. Here the police cannot arrest or investigate without prior approval from a magistrate. Things like defamation, public nuisance, or minor hurt usually fall here.

So simple difference cognizable = serious, police act directly, non-cognizable = less serious, court approval needed.