Mumbai, March 16: The BSE Sensex today dived almost 510 points -- its biggest single-day fall since February 6 --- due to a major sell-off amid political concerns after the Telugu Desam Party (TDP) decided to quit the NDA and moved a no-confidence notice against the government. Other Asian markets were also in the negative zone as investors fret over the prospect of a global trade war, accelerating selling pressure on the domestic bourses, brokers said.

For the third straight week, the flagship Sensex recorded a fall of 131.14 points, or 0.39 percent, while the NSE Nifty lost 31.70 points or 0.30 percent. Sentiment suffered a setback following fresh development on the political front after a key NDA ally, TDP, decided to quit the alliance and moved a no-confidence motion notice against the government, accelerating the selling pace by participants, brokers said.

The Lok Sabha could not take up notices for no-confidence motion against the NDA government with Speaker Sumitra Mahajan saying there was no order in the House and adjourned the proceedings for the day The 30-share Sensex tumbled by 509.54 points or 1.51 percent, its biggest single-day fall since February 6 when it had lost 561.22 points, to end at 33,176. Intra-day, it shuttled between 33,119.92 and 33,691.32 as metal, oil & gas, PSU, power, auto and banking stocks recorded widespread losses. The flagship index had lost 232.40 points in the previous three sessions. The broader NSE Nifty dipped below the 10,200-mark to hit a low of 10,180.25 before ending at 10,195.15, down by 165 points, or 1.59 percent.