Hi, there is a simple solution to your problem. I can create a script in PHP that you should host on a web server based in India. That PHP script will act as an intermediary between your Google Apps Script and your API service provider. Your Google Apps Script instead of making requests to the API server directly should make requests to that PHP script which will, in turn, forward those requests to your API service, and the responses returned from that API will be sent back to Google Apps Script.
If you'd like to discuss your project with me, then feel free to send me a message even when I appear offline. I typically reply back within a few minutes when online otherwise in a few hours when offline.