Drupal Sprint India is a gathering of Drupal enthusiasts. Any one who is interested in Drupal or you want to help in improving Drupal, you are invited.
Drupal has support for several local languages, so it will be good starting point to search for existing project working on your chosen language. You can apply to drupal.org for a new project in case language of your choice is not been translated currently. Details n the translation process of Drupal can be found here.
Anyone can contribute documentation to Drupal. You need not be an experienced writer to join documentation sprint. If you want to improve Drupal documentation you can join. You can read more about Drupal documentation sprint here. It will be worth reading the documentation hand book, to understand the documentation style and methodologies before you start.
For new Drupal developers, you should have the Drupal development environment set up as defined here. As new developer you need to decide you want to work on core or contributed module. More details on contributing code can be found here.
Yes, you can join the sprint to contribute to Drupal documentation or contribute in translating Drupal to local Indian language.