I had two round of interviews for ACI Payments Pune. For very first round I preferred for formals and for second time I preferred smart casuals (as it was Friday and I didn’t wanted my colleges to know that I had been for an interview). Frankly, I found no specific dress code compulsion. But to be on safer side, wear formals is what I would suggest.
I had 2 technical rounds that were telephonic followed by HR(telephonic)