In a world rich in climate knowledge but short on climate action, it is important to understand the political reasons behind the apparent failure of states to address this planetary crisis. One underexplored dimension of this phenomenon is the impact of broader geopolitics and rivalry, in specific the ability and willingness of potential and actual security and economic rivals to leave their contention at the gates of the United Nations Framework Convention on Climate Change (UNFCCC). This article focuses on India’s multifaceted approach to its ‘China challenge’ with and outside the climate regime. While conventional scholarship focuses on the security and economic dimensions of this rivalry, this study offers a distinct perspective that examines whether this rivalry might lead to a breakdown of cooperation and an increased potential for conflict and weaponisation of seemingly disconnected issue areas. Drawing on a comprehensive triangulation of policy documents, government statements and scholarly literature, this article evaluates the domestic and international factors shaping India’s climate-related China policies, including the countries’ unique economic ambitions, development imperatives, energy needs and global climate commitments. Furthermore, the article examines Sino-Indian interactions in international arenas such as the UNFCCC and Brazil, Russia, India, China, South Africa (BRICS), and how these interactions influence global climate governance.