Weak buying interest due to declining oil prices dragged Riyadh's Tadawul exchange down by 2.52%, closing at 5,966.02 points. Oil traded lower by around 2 per cent on Tuesday. As a direct impact, the Tadawul petrochemical index posted the largest decline (off 3.29%) among the sector indices. Market bellwether Saudi Basic Industries Corporation (Sabic) plummeted three per cent lower and ended at SR86.25.