Dear Pankaj,
As per the ratio decidendi of the judgment of the hon'ble High Court of Madras in Mettur Beardsel Limited case, it is enough that the employee has completed 4 years and 240 days of service in the fifth year to be eligible for gratuity under the P.G Act,1972. It is not correct that the application of 5 years continuous service is dependent on no. of the working days in a week for the definition of "continuous service" u/s 2-A of the PG Act,1972 includes all the authorised leave and holidays. If it is so urgent that you should leave this job immediately, get smoothly relieved and file your claim for gratuity afterwards before the Controlling Authority under the Act.