Hello. Since you have mentioned your masters is from IIM, I assume that you want to do your phd in management. Now, for the top IIMs and IITs, the registration dates are over. In fact, for the IIMs, the interview process has been completed and admission offers have been made. For IITs, interview process has been completed and results are awaiting.

So, for the top institutions, the whole process has been completed. However, you can go through individual private colleges  for their admissions.

Hope this helps.

All the best.