It is very difficult to suppress Arvind Kejriwal's voice, Punjab Chief Minister Bhagwant Mann said on Friday hours after the CBI summoned the Delhi chief minister on April 16 in connection with the excise policy scam case. While Punjab Minister Harjot Singh Bains described Arvind Kejriwal as a "revolution India is witnessing", many other AAP senior leaders from the state including Finance Minister Harpal Singh Cheema said the Delhi chief minister "cannot be silenced by such tactics".