Review of Regional Haze Situation for May 2024
1.1 In early May 2024, the prevailing winds, especially over the Mekong sub-region and the South China Sea, were light and variable as inter-monsoon conditions continued. Prevailing winds for areas located south of the Equator then transitioned into southeasterlies from mid-May onwards, indicating the development of the Southwest Monsoon. Winds located to the east of the Philippines continue to be easterly in May 2024. (Figure 1).
1.2 Rainfall was observed over most of the ASEAN region except for Java and the Lesser Sunda Islands, where conditions were drier. The increase in precipitation in the Mekong sub-region compared to April 2024 resulted in the reduction of hotspots in the sub-region. (Figure 1) The Alert level was downgraded to Level 2 on 6 May, Level 1 on 13 May and subsequently Level 0 on 23 May, signaling the end of the dry season for the Mekong sub-region.
1.3 The hotspot count in May 2024 for Peninsular Malaysia, Sabah and Sarawak were higher when compared to previous years. However, for Kalimantan and Sumatra, the hotspot counts for May 2024 were lower. (Figure 3). Elsewhere in the ASEAN region, especially in the Mekong sub-region, the number of hotspots remain comparable with previous years.
1.4 In May 2024, isolated to scattered hotspots were detected mainly in the Mekong sub-region and the Philippines, especially in the northern parts of Lao PDR and the southern parts of Myanmar where fire intensity and hotspot persistency were more pronounced. (Figure 4 and 5) During early May, moderate to dense transboundary smoke haze was observed over the northern parts of Lao PDR, the northern parts of Thailand, as well as the eastern and southern parts of Myanmar. The transboundary smoke haze was shown to drift in the north-east direction into the northern parts of Viet Nam and Lao PDR (Figure 6 and 7).
1.5 Hotspot activity remained mostly subdued in the southern ASEAN region except for a few persistent hotspots in the eastern parts of Peninsular Malaysia (Figure 4). Localised smoke plumes were observed to emanate from these hotspots on some days. (Figure 8)
