A small number of very old Amar Chitra Katha issues that were never renewed for copyright (specifically pre-1978 issues in the US public domain) might be found on Archive.org. However, this is less than 5% of the catalog. Do not assume everything there is legal.
The series provides a foundation for understanding Indian customs, festivals, and moral values. Amar Chitra Katha Collection Pdf
Let’s be realistic. The holy grail for collectors is a specific user-curated torrent known as the which clocks in at roughly 2.5 GB and contains over 600 issues in CBZ/CBR format (comic book archives that convert easily to PDF). A small number of very old Amar Chitra