Some websites offer the of the Sanskrit original, alongside a Tamil translation line-by-line. This is excellent for scholars.
: Provides access to scholarly works like the Some Aspects of the Vayu Purana by V.R. Ramachandra Dikshitar. vayu puranam tamil pdf
Many free PDFs online are abridged (summarized) or are scanned copies of old, poorly printed books. An unabridged version with all 10,000+ verses is rare in the public domain. Some websites offer the of the Sanskrit original,