A method implemented by at least one master sensor (14a, 14b, 54, 202) for providing quality data to a network node (16, 204), the method comprising: - receiving (208, 302) by the at least one master sensor (14a, 14b, 54, 202) sensor data from at least a fraction of a plurality of single-purpose slave sensors (11i, 11j, 52a,.., 52i, 200) distributed over a geographical area; - evaluating (44, 210, 304) by the at least one master sensor (14a, 14b, 54, 202), a data quality of sensor data of each single-purpose slave sensor (11i, 11j, 52a,.., 52i, 200) from which sensor data is received; - forwarding (46, 314), by the at least one master sensor (14a, 14b, 54, 202), to the network node (16, 204) at least a representation of the sensor data of each single-purpose slave sensor (11i, 11j, 52a,.., 52i, 200) of which data quality of the sensor data is higher than a data quality threshold; and - sending (48, 226, 232, 320, 322) by the at least one master sensor (14a, 14b, 54, 202), a feedback message to each single-purpose slave sensor (11i, 11j, 52a,.., 52i, 200) from which sensor data having a data quality lower than a data quality threshold is received, the feedback message being based on an updated reliability metric of said each single-purpose slave sensor (11i, 11j, 52a,.., 52i, 200), wherein sending the feedback message further comprises - sending (226, 320) to single-purpose slave sensors (11i, 11j, 52a,.., 52i, 200) having the updated reliability metric specifying that they are reliable, a message denying the received sensor data from said single-purpose slave sensors (11i, 11j, 52a,.., 52i, 200); - sending (232, 322) to single-purpose slave sensors (11i, 11j, 52a,.., 52i, 200) having the updated reliability metric specifying that they are unreliable, a message initiating termination of said single-purpose slave sensors (11i, 11j, 52a,.., 52i, 200). - receiving (208, 302) by the at least one master sensor (14a, 14b, 54, 202) sensor data from at least a fraction of a plurality of single-purpose slave sensors (11i, 11j, 52a,.., 52i, 200) distributed over a geographical area; - evaluating (44, 210, 304) by the at least one master sensor (14a, 14b, 54, 202), a data quality of sensor data of each single-purpose slave sensor (11i, 11j, 52a,.., 52i, 200) from which sensor data is received; - forwarding (46, 314), by the at least one master sensor (14a, 14b, 54, 202), to the network node (16, 204) at least a representation of the sensor data of each single-purpose slave sensor (11i, 11j, 52a,.., 52i, 200) of which data quality of the sensor data is higher than a data quality threshold; and - sending (48, 226, 232, 320, 322) by the at least one master sensor (14a, 14b, 54, 202), a feedback message to each single-purpose slave sensor (11i, 11j, 52a,.., 52i, 200) from which sensor data having a data quality lower than a data quality threshold is received, the feedback message being based on an updated reliability metric of said each single-purpose slave sensor (11i, 11j, 52a,.., 52i, 200), wherein sending the feedback message further comprises - sending (226, 320) to single-purpose slave sensors (11i, 11j, 52a,.., 52i, 200) having the updated reliability metric specifying that they are reliable, a message denying the received sensor data from said single-purpose slave sensors (11i, 11j, 52a,.., 52i, 200); - sending (232, 322) to single-purpose slave sensors (11i, 11j, 52a,.., 52i, 200) having the updated reliability metric specifying that they are unreliable, a message initiating termination of said single-purpose slave sensors (11i, 11j, 52a,.., 52i, 200).