New Delhi, July 6: Delhi's Anti Corruption Branch (ACB), controlled by the central government, has summoned former Chief Minister Shiela Dikshit for questioning in an alleged water meter scam. "We have served a notice to Shiela Dikshit," ACB chief M.K. Mee told IANS on Wednesday. He said the matter related to the buying of about 2.5 lakh water meters in 2011. The officer said a case was registered with the ACB in 2014 on charges of manipulating the tender process and favoring only one company.