Sensex drops 189 points to end below 28,000: Benchmark indices ended lower owing to selling among blue-chips even though the government eased the escalating worries about retrospective taxation yesterday. A weak monsoon forecast further dampened the sentiments. However, the losses are capped with a strong rally in the metal stocks after Bank of America-Merrill Lynch said the sector's return on equity will double by FY17 end. The Sensex was down 155.11 points or 0.6 percent at 27735.02 and the Nifty slipped 31.40 points or 0.4 percent at 8398.30. The market participants would closely watch the proceedings in parliament during the final part of the ongoing Budget session as the government hopes to pass the Goods and Services Tax (GST) and the Land Acquisition Bill.