Climate change poses profound and multifaceted challenges to environmental health. The World Health Organization has pinpointed that climate change is the biggest thread on population health. Among the most pressing issues are the rising intensity and frequency of heatwaves and the worsening of air pollution-both of which have far-reaching implications for human health. This talk will explore how climate change and natural climate variability influence air quality and thermal extremes, with a focus on their combined and individual effects on human health outcomes. We will examine the global trend of Hot-and-Polluted Episodes (HPE). The interactions between air pollution and heatwaves will also be discussed, including the synergistic effects that amplify health risks, particularly among vulnerable populations. Drawing on recent research and case studies from various regions, including Southeast Asia, this presentation will highlight the need for integrated climate and public health policies to mitigate current impacts and build resilience for the future.