Tussle between West Bengal CM Mamata Banerjee and Governor CV Ananda Bose was tarnishing the image of state and is a "shameful episode", Congress leader Adhir Ranjan Chowdhury said. Speaking about the defamation case filed by Bose against Banerjee after she said that women don't feel safe to go to Raj Bhavan, Chowdhury said CM should provide evidence.