Abstract The Indian subcontinent today houses about one-third of the global population and is one of the most vulnerable regions to future climate variability. This region has seen changes in civilizations, kingdoms and more recently political regimes, that were intricately linked to the changing environment over the mid–late Holocene. A comparative analysis of human–environment interaction within different regions at different time scales of the Quaternary is, however, lacking. In this paper we discuss the human–environment interactions taking case studies from two diverse time periods and geographically different regions from the Indian subcontinent. First, we review and analyse the role of environmental change in the evolution of Indus civilization on the northwestern Indian subcontinent during the mid–late Holocene and secondly, we discuss the role of both the anthropogenic activities and environmental change during the Anthropocene in shaping up the Bengal Delta. Overall, during the mid–late Holocene, Indus cultural transformations were driven by natural environmental changes, whereas the anthropogenic activities in the last few centuries have modified the Bengal deltaic landscape, which has intensified the impacts of natural disasters – in both cases a change in socio-political scenarios occurred. Such studies can be used as benchmarks to understand the future response of societies to environmental changes.

Abstract The National Gas Hydrate Program Expedition 02 was conducted in early 2015 using the Drilling Vessel Chikyu in the western part of the Bay of Bengal, India. During drilling off Vishakhapatnam, NE India, some bottom-simulating reflectors were penetrated, and numerous mass-transport deposits (MTDs) were identified. The recovered cores were composed of post-late Miocene muddy slope deposits containing the late Miocene–Pliocene hiatus that is widespread in that region. Based on detailed visual core descriptions and calcareous nannofossil biostratigraphy, two major MTD-rich intervals were identified: the Pleistocene interval above the hiatus, and the middle–late Miocene interval below it. Although the MTDs in both intervals are composed of variously coloured clay–silt blocks in an olive-black or olive-grey silty clay matrix (muddy MTDs), the Pleistocene MTDs consist of larger-sized blocks (mostly less than a few metres but with some >10 m) without clear shear fabrics, whereas the Miocene MTDs contain smaller blocks (<0.1 m) with asymmetrical shear fabrics. The muddy blocks are composed of older components (Pliocene–Cretaceous) compared with the depositional ages of the MTDs. The high abundance of MTDs above the hiatus and the depositional ages of the interbedded coherent layers indicate that large-scale MTDs occurred repeatedly during the Pleistocene. Such repeated MTDs contributed to maintaining the high sedimentation rate in this area and potentially provided stable pressure and temperature conditions for the formation of gas hydrates.