when a person can be arrested without any warrant

Section 41(1) of CrPC,1973 explains when a person can be arrested without any warrant. Section 41(2) of CrPC, 1973 states that subject to the condition in Section 42, a person cannot be arrested without a warrant and an order of the magistrate in case of non-cognizable offence and where a complaint is made.

Section 43(1) of the Code of Criminal Procedure (CrPC) states that a private person can arrest someone who commits a non-bailable offense or a proclaimed offender. The private person must take the person arrested to a police officer without delay. If there is no police officer, the accused must be taken to the nearest police station.
Section 41(1)(c) of the CrPC states that a person can be arrested if they have been proclaimed an offender under the Criminal Procedure Code or a State Government order. Section 41(1)(d) states that someone can be arrested if they are found in possession of stolen property.

Crpc sec 43

Any private person may arrest or cause to be arrested any person who in his presence commits a non-bailable and cognizable offence, or any proclaimed offender, and, without unnecessary delay, shall make over or cause to be made over any person so arrested to a police officer, or, in the absence of a police officer, take such person or cause him 10 be taken in custody to the nearest police station.
        If there is reason to believe that such person comes under the provisions of section 41, a police officer shall re-arrest him.
        If there is reason to believe that he has committed a non-cognizable offence and he refuses on the demand of a police officer to give his name and residence, or gives a name or residence which such officer has reason to believe to be false, he shall be dealt with under the provisions of section 42; but if there is no sufficient reason to believe that he has committed any offence, he shall be at once released.
Read more at: https://devgan.in/crpc/section/43/