<p>This article develops a hybrid pilot allocation (asynchronous progression-based) scheme for minimizing pilot contamination (PC) in cell-free (CF) massive multiple-input-multiple-output (m-MIMO) system. A CF m-MIMO system with spatially correlated channel has been studied. In this approach, the users are divided into good and poor users depending on their channel conditions. The poor users are then allowed to send their assigned pilots in different time slots, thereby avoiding PC. The good users send their pilots in the same time slot, thus experience PC. To reduce the PC in good users and improve system sum-rate, a progression-based method is deployed for assigning pilots to them. Two different combining strategies, the maximal-ratio and minimum mean square error techniques, have been considered for efficient channel estimation. Simulation results show that the proposed scheme has a superior performance with respect to the conventional schemes and is capable of achieving high system sum-rate and enhances user fairness.</p>