In this month’s Development Alternatives blog, Dr Soumen Maity explores the growing public health crisis caused by transboundary air pollution, with a particular focus on South Asia. The piece highlights how air pollution claims millions of lives each year and underscores the stark reality that nearly 99% of the global population is exposed to unsafe air. The blog makes a strong case for coordinated regional action, outlining why effective policies, technology-led solutions, and international collaboration are critical to tackling air pollution at scale and safeguarding public health.