First Aptitude round then Manager round whole process completed in one day. this is basic interview format for bpo job may differ according to project your are been interviewed . i attend interview in back 2013 so it may differ now

TCS interview questions cover a mix of HR-related topics like "Tell me about yourself," "Why TCS," and "strengths and weaknesses," along with technical questions on programming languages, data structures, databases (like DBMS, RDBMS, normalization), and specific subjects like OOP, C++, and Java. Expect questions about project experience, problem-solving, handling difficult situations, and behavioral scenarios like working with different teams or under pressure