Are blood oxygen app and ECG apps unavailable in India?

Thanks for asking about the ECG feature.

Check here for availability in your region: ECG

ECG requires the current non-beta version of iOS and watchOS. For additional help with the ECG feature on your Apple Watch, take a look at these articles.

Heart rate notifications on your Apple Watch - Apple Support

Taking an ECG with the ECG app on Apple Watch Series 4 or later - Apple Support

If you have any other questions, please reach out to our team here: https://apple.co/HeartFeatures. If you believe that you are experiencing a medical emergency, please dial your local emergency services.

Take care.

Contact apple support here;

We're here to help

Yes they are available in India,did you buy the watch in India?.