Senior ACB officials claims that the anti-graft body has been investigating the case with approval from Lieutenant Governor (LG) Najeeb Jung.
"We will not allow any interference in the ongoing investigation," Meena said.
Meena had earlier this week sent notice to over a dozen Delhi Government officials including Chief Minister Arvind Kejriwal's secretary Rajendra Kumar for questioning in the alleged Rs 100-crore CNG fitness scam.
The Commission of Inquiry will be headed by retired Delhi High Court judge Justice S N Agarwal and its terms of reference will soon be announced by Vigilance Minister Manish Sisodia.
The AAP had accused Lt Governor Jung of trying to hush up the scam. Asked whether Jung or former Chief Minister Dikshit would be questioned in connection with the alleged scam, Delhi Home Minister Satyendar Jain said it would be up to the Commission to decide.