Besides Mittal, action has been ordered against chief project manager H C Tewari, project manager K R Sudan, assistant engineer Rajesh Singh, engineer Lal Chand, former project manager Genda Lal and additional project manager Rajesh Pal, he said, adding four of them have already been placed under suspension.
The state government had yesterday shunted out Mittal from the post of Managing Director UP State Bridge Corporation.
A portion of the flyover coming up in Prime Minister Narendra Modi's Lok Sabha constituency collapsed on Tuesday, crushing a mini bus, cars and two-wheelers. Officials initially said 18 people were killed, but the toll was revised to 15 later.
The chief minister has asked the state Public Works Department and other agencies carrying out construction works to take all steps to prevent recurrence of such incidents.
He issued a check list needed to be strictly followed in all construction works. The points in the list included proper barricading of the construction site and making alternative arrangement for traffic movement.
The official said the chief minister has directed authorities concerned to make third-party inspection necessary of all important works to ensure quality.