Under the Limitation Act, 1963, where after the institution of a suit, a new defendant is added without…

The ordinary rule treats the suit against the newly added defendant as instituted when he is made a party. Section 21 permits an earlier date upon a court direction for an omission caused by a good faith mistake, but no such direction is stated here.

Why not "Be deemed to have been instituted on the day he first appears in person or through agent to defend himself."? The defendant's first appearance is not the event that section 21 uses to fix the ordinary institution date against a newly added party. Appearance may occur later in the proceedings. The relevant event is his addition as a party, subject to the statute's specified exceptions.

Why not "Be deemed to have been instituted when the suit was originally filed."? Original filing does not automatically govern limitation against someone added later as a defendant. An earlier deemed date requires an applicable statutory exception or the court's direction concerning a good faith omission. Neither is established by the stated facts, which exclude the devolution situation.

Why not "Be deemed to have been instituted on the day when notice of the suit is received by him."? Receiving notice informs the defendant about the proceedings, but it does not replace the addition date specified by the Limitation Act. Service and institution serve different procedural purposes. For the ordinary rule posed here, the suit is deemed instituted against him when he becomes a party.