The ACB had recorded Mishra's detailed statement last week and was to question him again today but he had sought deferment of his questioning for the day due to personal reasons.
"He cited personal reasons seeking exemption from the questioning today. He will come for the questioning next week," said a senior ACB officer.
Delhi Chief Minister Arvind Kejriwal's private secretary Bibhav Kumar too was questioned yesterday by the ACB in connection with the "scam."
Last year in August, Dikshit was "examined" by the ACB officials in connection with her alleged involvement in the tanker scam.
The Kejriwal-led AAP government had in June 2015 constituted a fact-finding committee to go into the alleged irregularities in procuring some 385 stainless steel water tankers by the DJB.
The Delhi government in June 2016 had sent a report of the fact-finding committee to erstwhile Lieutenant Governor Najeeb Jung following which an FIR was registered in the case.