A system and method for controlling network congestion are provided. The method may include one or more of the following operations. One or more alert signals corresponding to one or more alert events of one or more urgency levels may be obtained at a first time of interest. A network condition of the network at the first time of interest may be obtained. A congestion assessment (CGA) at the first time of interest may be performed based on the network condition. A first communication protocol for sending the one or more alert signals may be determined based on the CGA. A first batch of alert signals of the one or more alert signals may be caused, based on the first communication protocol and the urgency levels of the one or more alert signals, to be sent via the network.