CPUs are relatively sturdy and quite light, so any way you can carry it is fine. Push it into a sponge or styrofoam pad so that pins do not get bent. I would put it in the carry-on luggage since I would prefer keeping an eye on it, just because it's valuable and small which makes it an easy target for thieves.
[EDIT] With the CPU pins in the sponge, insert it into a anti-static. Most computer parts come in one, so you probably can find one even if you do not have the original.
Couriering it does not seem like a reasonable option because that is quite costly. Even a small package like that shipped to India with tracking or insurance probably costs a significant percentage over what a 2 year old CPU is worth.