I am planning to purchase an iWatch 6 (GPS Cellular) in Dubai, however I'd be going to India for a year. Would this watch work in India on cellular?

There are 2 cellular radios used by the Apple Watch

• The Canada, U.S., Mexico, Puerto Rico radio
• The rest of the world radio

So in theory it will work.

HOWEVER, be aware that Apple Watches have regional software installed. If Dubai has government restrictions on specific features, those features will not work when you get home.

Here are the features enabled in different countries

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

Make sure the ones for the UAE and Dubai are what you want, and that something you expect to be there is missing.

Also the warranty is regional, so you may not be able to get warranty repair unless you return to Dubai.