Both fell for the fourth straight day.
North Korea upped the ante, defying the US President's "fire and fury" warning and threatening to strike its military base in Guam. The markets have already been reeling under the regulatory clampdown after Sebi's Monday directive imposing trading restrictions on suspected shell companies.
After opening lower, the Sensex recovered, but only to slip again to hit a low of 31,422.80 before settling down 266.51 points, or 0.84 per cent, at 31,531.33. The level was last seen on July 7 when it ended at 31,360.63.
The Nifty after shuttling between 9,776.20 and 9,892.65, ended the day lower by 87.80 points or 0.89 per cent at 9,820.25.
Lower-than-expected earnings by Tata Motors, Eicher Motors and a few other companies dampened risk appetite. Tata Motors emerged as the top loser among Sensex constituents.