You have to do it in multiple steps:
1) Download app from Indian IOS app store
2) Go to 'Add a new device' section of app
3) It will give you option of selecting language - Select 'English (Indian)'. Follow the steps - in the end it will give an error '15:1:26:0:2'. But it will say that language will be downloaded to device (dont worry - it will download when you follow below steps).
4) Login into your Amazon account on browser. Go to 'Manage Your Content and Devices' and in settings, change country to US. You might have to create a dummy US address for this if no US address set in your address list. Create any US address.
5) Restart the process of connecting echo dot with your app but use 'English (US)' as your default app langauge. It will take your through process of connecting your echo dot with your home wifi. You will be able to do things on app as US Resident now - play songs etc or get weather updates. Once wifi is enabled, device will download langauge pack on device on own in 30 minutes.
6) Deregister echo dot from your app.
7) Change country settings in your amazon account back to India.
Go through connection process again of app with Echo dot but select 'English (India)' now and you will be able to connect to Amazon India account. You will be able to see Indian skills as well.