Q: How long does it take to unblock an Airtel SIM? A: The unblocking process usually takes a few minutes to an hour.
You unblock it remotely. You need a SIM replacement : how to unblock airtel sim
If your Airtel SIM works fine, but you want to use a different operator's SIM in your Airtel-locked device (or vice versa, though SIM cards themselves are rarely "locked" to a network in the same way phones are): Q: How long does it take to unblock an Airtel SIM