Can I buy Apple Watch 6 in USA for India?

There are 2 Apple Watch cellular radios

• Canada, U.S. Mexico, Puerto Rico, Dominican Republic, Ecuador

• The rest of the world

Carriers will not attempt to connect to an Apple Watch that does not use the correct radio.

If you do not get your Apple Watch in your own country, you may have to return the Apple Watch to the country where purchased to get warranty service.

If you do not get your Apple Watch in your own country, there may be country specific restrictions in the installed Apple Watch software that prevent features from working when you get home.

https://www.apple.com/watchos/feature-availability

the cellular part will not work outside of usa, canada and mexico

and not sure if the warranty will be valid in other countries