A couple of times during the first day's play, on Wednesday, Gambhir had run-ins with medium pacer Watson and spinner Simon Katich. The first incident happened with Watson after the Australian hurled some abuses at the batsmen and while taking a run Gambhir's stuck out his elbow that hit Watson, who seemed to have taken serious offence.
Gambhir has been charged under clause C1 Level 2 of the code which states that players "shall at all times conduct play within the spirit of the game as well as within the Laws of Cricket".
Watson has been charged under the same clause, C1, but as a Level 1 offence.
The charges were laid by on-field umpires Billy Bowden and Aleem Dar and third umpire Suresh Shastri. Match Referee Chris Broad will hear it after the second day's play Thursday.
Level 2 penalties range from a fine of between 50 percent of the player's match fee up to 100 percent or a ban of one Test or two ODIs. Level 1 penalties range from an official reprimand and/or a fine of up to 50 percent of the player's match fee.
The second incident happened with Katich, when the bowler came in Gambhir's way to deny him a single. Gambhir looked furious and a heated exchange of words took place and umpire Billy Bowden had to step in to separate them.India's Gautam Gambhir may still play the fourth and final Test in Nagpur after the International Cricket Council said that pending a hearing into the opener's appeal against the one-Test ban, he could continue playing under Code of Conduct regulations.
The ICC said is a statement that its Legal Counsel will appoint a Code of Conduct Commissioner within 48 hours and that the appeal will be heard within seven days of the Commissioner's appointment.
The final Test against Australia starts in Nagpur from November 6 and if a decision doesn't arrive by then, Gambhir would be eligible to play in that match.
The India opener pleaded guilty to the charge levied against him for elbowing Australian bowler Shane Watson while attempting a run on the first day of the third Test at the Ferozeshah Kotla ground and was handed a one-Test ban by match referee Chris Broad.
However, if the left-hander fails to overturn the match referee's verdict, he will have to bear the cost of the appeal.