Why was Dipa Karmarkar under house arrest on her birthday

Dipa Karmarkar, our able gymnast, who is the talk of the town for qualifying for the finals in Rio Olympics, has no regrets that she is under house arrest. Her strict coach Bishweshwar Nandi has seized her SIM card and does not allow anyone to speak to her. Nandi does not want Karmakar to lose focus and he just want her to concentrate on the game. This is the reason why Dipa Karmakar is under house arrest. Her only companion at the Olympic Games is weight lifter Saikhom Mirabai Chanu.