Addressing a massive gathering of Left Democratic Front workers, who laid a siege in front of the Secretariat in Thiruvananthapuram, Karat said Chandy should step down from office if he had any accountability to the people.
"The Congress has set shameless standards to see that their leaders are not accountable for what is happening in their ministries and offices," he said.
While there were instances of chief ministers and Union ministers resigning on moral grounds earlier, the party had now stooped to low levels to protect corruption, Karat said.
The Congress-led government in Kerala had called the Indo-Tibetan Border Police to protect a chief minister who was facing allegations of corruption.
"They are supposed to protect the borders in Jammu and Kashmir," he said.
Former prime minister H D Deve Gowda said only an impartial probe by a judicial commission led by a high court judge could come out with the truth on the solar scam. The chief minister should step down to make way for such a probe, he said.
"The government cannot move ahead with an undeclared emergency all the time in view of the people's struggle. At least Chandy should step down to come out from the tangle," Gowda said.
CPI general secretary Sudhakar Reddy said Chandy could not escape moral and political responsibility in the solar scam.
Corruption scams sweeping the nation, involving "mind-boggling amounts" were alarming, he said.
He said the chief minister should not try to cling to office "shamelessly" after his office assistants and personal staff were found to be involved in the solar scam.
"Only a judicial inquiry can come out with the truth," he said.
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