The SATAN project in the UK (Stratospheric Aerosol Transport and Nucleation), funded by anonymous private donations, has faced criticism and controversy due to concerns about the potential unintended consequences of releasing SO2 into the stratosphere and the lack of transparency and public scrutiny in the planning and execution of the experiments. The weather modification project took place between 2021-22.

https://www.geoengineeringmonitor.org/technologies/stratospheric-aerosol-injection