Answer: January 6
Notes: National Siddha Day is observed every year in India on January 6 to mark the birth anniversary of Sage Agathiyar, regarded as the father of the Siddha system of medicine. The day coincides with the Ayilyam star in the Tamil month of Margazhi. The first National Siddha Day was observed on 4 January 2018. The 9th National Siddha Day falls on 6 January 2026.
