Older TSC fonts have limited line-height metadata. Fix: In Word/Writer, increase line spacing to 1.5 or 1.8.
You are typing in Unicode, but TSC Avarangal is a legacy (TSCII) font. Fix: Use a TSCII-to-Unicode converter (like Azhagi, or online converter at TamilTools.com). Alternatively, copy-paste TSC text from a source that uses the same encoding. tsc avarangal tamil font download upd