Dear Ashish,
Better you go through section 25B of the Industrial Disputes Act,1947 and section 2A of the Payment of Gratuity Act,1972 both of which is almost similar to each other in defining the concept of continuous service. To put it simple, in order to determine whether a workman/employee has rendered continuous service under the same employer/establishment within a period of 12 consecutive calendar months, it is to be confirmed whether he has worked for a minimum of 240 days. These 240 days include not only the actual no of days he worked but also the days of interruptions due to holidays, authorised leave, lay off, lock out, strike which is not illegal, absence due to temporary disablement.