15. Gummidipoondi

All India Anna Dravida Munnetra Kazhagam held the seat; the winning margin narrowed from 19.0% to 0.1%.

• Won on a lower shareIts own vote share fell 15.7% — it held because the rest of the vote was more divided.
• New challengerPattali Makkal Katchi (PMK) finished second with 40.3% — it did not contest here in 2001.
• Vote fragmentedThe top two took only 80.7% between them, down from 93.1% — the field split more ways.

Written from the constituency figures by a fixed set of rules — no language model.