Dow Jones Industrial Average index faced its worst day in three months giving up more than 200 points on Tuesday. Blue chip index plunged 1.57% or 203.66 points and closed at 12,759.15 with 29 of 30 stocks posting losses. Industry sector overall declined 2.7% as aluminium giant Alcoa and construction and mining-equipment producer Caterpillar fell 4% and 3.8% respectively. Merck & Co lost 2.6% after the drug-maker reported lower than expected profit forecast.