Sorry to hear about the issues you're having with your WiFi since moving. The reason you are having trouble is due to the fact that India is not a supported country for Nest WiFi. With WiFi devices, they are often not usable from one country to the next due to differences in local WiFi standards and regulations. As of right now, Nest WiFi is not supported in India and you will need to investigate a local option as a replacement.
If there's anything else I can do for you, please let me know.