According to the latest World Bank report on the global health cost of particles with diameter less than 2.5 microns (µm) (PM2.5) air pollution, Uzbekistan has the second highest annual average PM2.5 concentration among the countries in Central Asia. This report summarizes the main results from a technical assessment of air quality in Tashkent (Part I) that informed the definition of sectoral policies and measures (PaMs) in the roadmap for air quality management (AQM) improvement in Uzbekistan (AQM roadmap, Part 2). The report is part of a series of underlying studies on air quality in Central Asia that inform the dialogue with the government and pave the way for a comprehensive regional air quality assessment. The technical assessment for Tashkent aims to assess the air quality in the city using a scientific approach to air quality analysis, with a main focus on particles with diameter less than 2.5 microns (µm) (PM2.5). PM2.5 has been identified as the pollutant of the gravest health concern according to the World Health Organization (WHO) and is globally considered to be a critical air pollutant for which concentration targets need to be put in place.