Arvind Kejriwal, the Chief Minister of Delhi, today alleged "dangerous" tampering of Electronic Voting Machines (EVM) to rig polls and demanded that the April 23 Delhi municipal elections be deferred so that paper ballots can be usd. "We urge the Election Commission to reveal the EVM software to the country," the Aam Aadmi Party chief said, accusing the powerful poll body of "making a mockery" of elections. The allegations follow reports that an EVM only issued slips with the BJP symbol during a trial in Madhya Pradesh, where by-polls will be held in two assembly seats on Sunday.