Illuminating Change: Using Satellite Nighttime Lights to Track Human Footprints in India’s Protected Area Buffers

Abstract. This study assesses increasing human activity in Ecologically Sensitive Zones (ESZs) surrounding India's Protected Areas (PAs) using NASA's Black Marble Nighttime Light (NTL) data processed through Google Earth Engine (GEE). Radiance trends were analysed during dry-season months (February-May) across 631 ESZs for 2013, 2018, and 2023, with statistical validation using high-resolution imagery. Results show statistically significant increases (p < 0.05) in artificial illumination across 84% of ESZs, with mean radiance increases of 234% in high-growth zones. Statistical analysis reveals that infrastructure development and tourism are primary drivers, with 89% of ESZs showing spatial expansion of anthropogenic influence covering an additional 847 km² over the study period. The analysis highlights both regional disparities and common trends, such as intensified radiance along highways and around pilgrimage or tourist sites. By integrating NTL trends with administrative boundaries and land-use datasets, the study demonstrates how remotely sensed illumination data can complement conventional field assessments, offering a rapid, repeatable, and cost-effective tool for detecting emerging development pressures. The findings not only highlight areas where conservation interventions are urgently needed, but also illustrate the utility of NTL-based monitoring for urban and rural sustainability planning. This further supports evidence based decision making, regulating permissible development in ESZs, and fostering coexistence between human settlements and critical ecosystems.