New Delhi: Delhi's Anti Corruption Branch, controlled by the central government, on Thursday issued fresh summons to former Delhi Chief Minister Sheila Dikshit for questioning on August 26 in an alleged Rs 400-crore water tanker scam. "We have issued notice to Sheila Dikshit for questioning on August 26 in connection with Water tanker scam case," ACB chief M.K. Meena told reporters here. Earlier, the ACB had summoned Dikshit for questioning on July 6 in a matter related to buying of about 2.5 lakh water metres in 2011. The officer said a case was registered with the ACB in 2014 on charges of manipulating the tender process and favouring only one company.