Games : How to conquer India in EU4?

I am playing as Portugal and my goal from the beginning of the game has been to conquer the entire Indian subcontinent (or at least a very sizable portion) by the game's end. I thought this wasn't too ambitious, and indeed by the beginning of 1600s I held south India. I thought the nice casus belli I acquired earlier in the game to be able to freely conquer Asian and African primitive nations would work nicely. However, something set me back significantly. Since I held Goa from the beginning of the game, two Indian nations holding about 1/3 of India westernized (picture below, see the icon to the right of Bahmanis signifying technology group). This was apparently because they bordered a nation that was Western and significantly more advanced than they were for a very long time (I acquired Goa early 1500s).

Now my casus belli is gone and I need to fabricate claims for every single province. Not only that, but being westernized, their troops will be much more advanced (and since this is India also very numerous - their numbers were already challenging before westernization and I had to acquire alliances in India to this end).

So, two questions:

• What methods can I use to continue the conquest?


• How do I prevent the AI from westernizing in the first place?