Thank you for reaching out.
If I understand correctly you want to implement a geographic-based routing to your application using Traffic Manager behind Azure Front Door.
Actually, it is not a best practice to combine Traffic Manager and Front Door together. For most solutions, you should use either Front Door or Azure Traffic Manager, but not both. Traffic Manager is a DNS-based load balancer. It sends traffic directly to your origin's endpoints. In contrast, Front Door terminates connections at points of presence (PoPs) near to the client and establishes separate long-lived connections to the origins. The products work differently and are intended for different use cases. This is currently documented here.
As your "Ultimate aim of my task is to eliminate that latency to increase Performance"
I think just using Azure FrontDoor will better as it provides content caching and delivery (CDN) which will help reduce latency.
I understand that Front Door will reach out to the origin for the data, which is not cached, in this case it will help if you could create another instance of your web app in the South India region. You can add this web-app as a backend to your Front Door something similar to this tutorial here where the configuration uses equal weighted and same priority backends, which means that Azure Front Door directs traffic to the closest available site that hosts the application. This will help reduce latency.
To implement Lowest latencies-based traffic-routing using Front Door you can deploy origins in two or more locations across the globe which will improve the responsiveness of your applications by routing traffic to the destination that is 'closest' to your end users. Latency is the default traffic-routing method for your Front Door configuration. This routing method forwards requests from your end users to the closest origin behind Azure Front Door. This routing mechanism combined with the anycast architecture of Azure Front Door ensures that each of your end users gets the best performance based on their location. You can find more information here on how traffic is distributed between different origins in Azure Front Door.
Hope this helps! Please let me know if you have any additional questions. Thank you!
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