Benchmark index Sensex crashed over 1,200 points to 73,604.03 during afternoon trade on Thursday, while Nifty fell 1.5% to below 23,100. A rise in the US benchmark Treasury yield to its highest level since 2007, elevated crude oil prices and weakness in the rupee contributed to the decline. IRDAI's proposed overhaul of insurance commissions also dragged insurance and banking stocks.