Delhi Chief Minister Arvind Kejriwal, in his first political rally in Assam, today hit out at Himanta Biswa Sarma for his warning on a remark inside the Delhi Assembly, saying open threats don't befit a Chief Minister. He also questioned Mr Sarma's leadership and said he has only done "dirty politics" in the last seven years. The Assam Chief Minister had challenged Mr Kejriwal to repeat his charge that there are cases against him in other states.