Deep convection in the Asian summer monsoon is a significant transport process for lifting pollutants from the planetary boundary layer to the tropopause level. This process enables efficient injection into the stratosphere of reactive species such as chlorinated very-­short-­lived substances (Cl-­VSLSs) that deplete ozone. Past studies of convective transport associated with the Asian summer monsoon have focused mostly on the south Asian summer monsoon. Airborne observations reported in this work identify the East Asian summer monsoon convection as an effective transport pathway that carried record-­breaking levels of ozone-­depleting Cl-­VSLSs (mean organic chlorine from these VSLSs ~500 ppt) to the base of the stratosphere. These unique observations show total organic chlorine from VSLSs in the lower stratosphere over the Asian monsoon tropopause to be more than twice that previously reported over the tropical tropopause. Considering the recently observed increase in Cl-­VSLS emissions and the ongoing strengthening of the East Asian summer monsoon under global warming, our results highlight that a reevaluation of the contribution of Cl-­VSLS injection via the Asian monsoon to the total stratospheric chlorine budget is warranted. Asian summer monsoon | convective transport | very-­short-­lived ozone-­depleting substances | stratospheric ozone The Asian summer monsoon (ASM), a significant element of the climate system, has been studied as a regional weather pattern for centuries. Only in recent decades has its role in global constituent transport been recognized, largely owing to observations made from satellites (1). The ASM is of particular interest because its associated deep convective systems rapidly transport air masses from the planetary boundary layer (PBL) in one of the most polluted regions on the planet to the upper troposphere and lower stratosphere (UTLS). An annually recurring layer with a distinct chemical signature and aerosol composition forms at the tropopause level within the ASM UTLS anticyclone during boreal summer (2–5). Detailed information on the chemical and microphysical changes in the UTLS induced by this annually recurring transport process is necessary for the accurate representation of the role of the ASM in chemistry-­climate models. Targeted measurements using high-­altitude research aircraft, in addition to ground-­based and balloon-­borne observations, provide data essential for understanding physical processes and constraining chemistry-­climate models. Two prior experiments provided valuable measurements of trace gases and aerosols in the region of the ASM anticyclone (6–8). The Asian summer monsoon Chemical and Climate Impact Project (ACCLIP), a field campaign conducted in summer 2022 using two high-­altitude aircraft, the NSF National Center for Atmospheric Research (NCAR) Gulfstream V (GV) and the NASA WB-­57, represents the latest large-­scale effort of this kind. The ACCLIP campaign conducted a total of 29 research flights over the northwestern Pacific from July 31 to September 1, 2022, from an airbase in the Republic of Korea (see SI Appendix, Fig. S1 for flight tracks). The flights sampled air masses lofted by convection both inside and near the eastern edge of the ASM anticyclone. The observations include a large suite of trace gases and aerosols, mostly at altitudes between 12 and 19 km above sea level (asl), a layer not accessible by commercial aircraft. The data represent the largest set of in situ atmospheric composition measurements in the ASM region (see SI Appendix for further details).