Planetary analog sites in the Indian subcontinent and the Indian Ocean: Underexplored environments suited for astrobiological and space research

A central objective of astrobiology is to evaluate the habitability of other planetary bodies, and given the high cost and logistical complexity of space missions, preliminary investigations of planetary analog sites are a critical step in supporting and de-risking future exploration efforts. Planetary analog sites are extreme environments on Earth that exhibit one or more environmental, geological, geochemical, or biological characteristics that are analogous to conditions expected on other planetary bodies. Understanding how life persists in planetary analog sites is essential for advancing our knowledge of extraterrestrial habitability. They provide valuable opportunities to study life's resilience and to test life-detection instruments in realistic settings. In this review, we present the first comprehensive synthesis of over 30 planetary analog field sites located across the Indian subcontinent and the surrounding Indian Ocean region. These include high-altitude glaciers, alkaline lakes, hypersaline basins, hot springs, and cold desert ecosystems. Although these environments remain largely underexplored in the context of astrobiology, they exhibit strong environmental parallels to planetary conditions and offer significant potential for advancing microbial ecology, biosignature detection, and geobiological research. As the scientific community prepares for the next generation of deep space missions focused on the search for life beyond Earth, we call for a broader geographical and conceptual inclusion of analog sites. By highlighting the environmental diversity and scientific value of these under-characterized regions in South Asia and their marine periphery, this review contributes a vital and previously underrepresented perspective to planetary analog research. This review fills a critical gap in the global planetary analog landscape and aims to stimulate interdisciplinary investigations across planetary science, microbiology, and life-detection technology development.