Yadav, Kolkata Knight Riders' part-time off-spinner, was reported during his side's defeat in the last night's final against Chennai Super Kings and has been placed on the 'warning list'.
"After all video evidence of the match was taken into account, on-field umpires Rod Tucker and Kumar Dharmasena along with third umpire S. Ravi felt that there was a flex action in his elbow beyond the acceptable limit when bowling during the match," a release stated.
Before Yadav, his team-mate Sunil Narine, Dolphins' Prenelan Subrayen and Adnan Rasool and Mohammed Hafeez of Lahore Lions were also reported for illegal action.
Under the CLT20 Suspected Illegal Bowling Action policy, Yadav may request an Official Assessment from the BCCI Suspect Bowling Action Committee.
If a player receives a report while on the warning list, the player shall be suspended from bowling in any matches organised by the BCCI until such date as he is cleared.
A player suspended from bowling may continue to be selected to play in matches, however he will not be entitled to bowl.