As Executive directors are generally considered as drawing managerial remuneration from the company hence they are not entitled by law for payment of sitting fee.
However as per DCA if you want to pay sitting fee to the Executive directors like MD then you may pay but that would be counted for the purpose of calculating the overall managerial remuneration limit.
Sitting fee paid to directors does not amount to their remuneration. new provisions in the Companies Act will come where indipendent director will be paid good amount of sitting fee.