The Indian equity benchmarks extended losses in noon deals after staging a gap down opening on Wednesday. The Sensex fell as much as 800 points and Nifty 50 index dropped below 17,900 after relinquishing its important psychological level of 18,100 amid weak cues from global markets. Investor sentiment took a knock globally after a drone attack on UAE's Adnoc pushed crude prices higher and equity markets down across the world, analysts said.