 Night-time light observations from remote sensing have become increasingly important for understanding human activities and their associated environmental impacts. Advances in sensor technology, algorithms and products have enabled more accurate and timely measurements of night-time light levels, which can be used to track urbanization, socioeconomic dynamics, armed conflict and disasters, fisheries, energy use and climate change. These advancements are also leading to deeper insights into the changing world through multidisciplinary and interdisciplinary analyses of night-time light observations. This article was authored by Min Zhao, Yu Yu Xiu, Xu Atsuli and others.