As of my last knowledge update in September 2021, the "Aditya-L1" mission by the Indian Space Research Organisation (ISRO) was a planned mission to study the Sun.
Please note that there may have been developments or changes in the mission since then, so it's a good idea to check the latest information from ISRO or reliable sources for the most up-to-date details.
Here is a detailed description of the Aditya-L1 mission as of my last update: