Remote sensing of coal fires in India: A review

Coal fires are a persistent threat to major coal producing countries in the world. Alongside massive wastage of coal resources, coal fires pose enormous constraints to mining operations in adjacent areas. Beyond its dire denouement for a country's economy, coal fires pose potential risk to the environment, infrastructure and human health at local and regional scales. Owing to its dynamic nature and widespread occurrence, remote sensing provides the most cost-effective technology for mapping and monitoring of coal fires in India and the world over. This work presents a brief discussion on the principles of various remote sensing techniques and an in-depth review of the applications of remote sensing as a reliable tool to detect and monitor coal fires in India. While we review the capabilities and efficiencies of various remote sensing techniques, implemented since its inception in the late 1980s, we also highlight their limitations and advantages. Also, included are a broad overview of coal and coal fires in India, factors inducing them and their impact on the environment. Finally, we discuss the existing knowledge gaps, prospective challenges, urgent requirements and recommendations for extending the scope of remote sensing based coal fire investigations in the future.