A key index measuring crude tanker spot market strength has plummeted to its lowest level in 10 months as aframaxes, suezmaxes and VLCCs all retrenched since a March peak.

The Baltic Dirty Tanker Index fell nine points to 1,137 on Monday, marking a one-week decline of 6.7% and a 31.1% slump since the index peaked at 1,648 on 22 March.