The National Inventory Report 2021 (NIR 2021) gives a detailed and comprehensive description of the trend and the methodologies applied in the Austrian air emissions inventory for the greenhouse gases carbon dioxide, methane, nitrous oxide, HFC, PFC, SF6 and NF3. With this report, Austria complies with its reporting obligations under the EU Monitoring Mechanism as well as the UNFCCC and the Kyoto Protocol by providing transparent and verifiable documentation. It contains Emission data by sector for the years 1990 - 2019 as well as Information on Emission factors, activity data and other basic data for emission calculations. Moreover, the report provides documentation of the national inventory system and quality Control and assurance activities as performed by the accredited Inspection Body for Inventories (ISO/IEC 17020).