ROBOTICS….
In India , Robotics is still in progressing phase, so it will be better if you go for Mechatronics branch rather than pure Robotics.
With Mechatronics , your option for other fields will be open and if you still want to focus on Robotics ,you can focus . You can do your final year project in Robotics only.
And as for M.Tech in Mechatronics ,you can do that in NITK ,from where I am doing my M.Tech. NITK has a very good facility with mechatronics . You can have different Labs where you can work.
Or , IIT patna also has the Mtech mechatronics brach