Update: Folks are reporting that it is not working on their devices yet. I guess it is going to be rolled out sometime later today considering the video above was posted by Google India team just a few minutes ago.
Update: Video is now private. Google India probably realized that it was not yet ready for public viewing.
Update: It is live now. :)
Google seems to have finally launched voice navigation for Android users in the Indian market. Here is a video showcasing the functionality: