As a result, they have been declared 'withdrawn' from the current season of the I-League and banned for another two campaigns.
However the period of suspension for Mohun Bagan could be extended in the next meeting of the committee on January 9.
In the much-anticipated Kolkata derby this season, Mohun Bagan and India international midfielder Syed Rahim Nabi was injured after a missile was thrown from the gallery in protest of the referee's decision to give marching orders to Odafa Okolie.
Mohun Bagan, in their defense, had claimed that East Bengal, the organizers of the match, were unable to provide proper security to the players which has been refuted given that the Green and Maroons also play their home games at the Salt Lake Stadium and are very much aware of the security arrangements.
Justice A.K.Ganguly was appointed by the AIFF to review whether it was a case of Force Majeure or not, as Bagan claimed.
In his report, he concluded that the decision of the Mariners for not participating in the Kolkata derby in the second half cannot be supported on the ground of Force Majeure and hence have been found guilty.
The I-League Core Committee will meet again on January 9 to review the decision.
The announcement has come as a shock decision for the century-old Kolkata club, as they find themselves out of the most prestigious tournament of the nation. The club, which had gifted Indian football its first coveted trophy in 1911 by beating East Yorkshire Regiment, are now facing serious question marks about their immediate future.