Each year, the Emissions Gap Report provides an updated assessment of the gap between i) estimated future global GHG emissions if countries implement their climate mitigation pledges and ii) the global emission levels from least-cost pathways that are aligned with achieving the Paris Agreement goal of limiting global warming to well below 2°C and pursuing 1.5°C. This difference between where we will likely be and where we need to be is now well known as the ‘emissions gap’. This year, the new or updated NDCs as well as officially announced mitigation pledges for 2030, with a cut-off date of 30 September 2021, are included in the assessment. The report is organized into seven chapters, including this introduction. Chapter 2 assesses the trends in global GHG emissions and how they are affected by COVID-19, and provides a global and G20-member-specific overview of new, updated and announced NDCs. Chapter 3 provides an assessment of net-zero emission pledges. Chapter 4 updates the assessment of the likely emissions gap in 2030, based on new or updated NDCs as well as officially announced mitigation pledges for 2030. The chapter then looks at the implications of the emissions gap on the feasibility of achieving the long-term temperature goal of the Paris Agreement. Chapter 5 assesses the extent to which COVID-19 fiscal rescue and recovery measures to date can support low-carbon or high-carbon development. It also looks at the disparities between high-income and developing countries. Chapter 6 assesses the role of methane in the NDCs and in bridging the emissions gap, and considers options for cost-effective reductions of the otherwise growing emissions of methane. Finally, chapter 7 looks at the potential role of market mechanisms in implementing NDCs and enhancing future ambitions, and discusses what is required to make the use of markets environmentally effective, transparent and credible.