The Indian stock market extended sharp losses on Wednesday, with the Sensex and the Nifty falling around 0.75% each as Tata Sons Chairman N Chandrasekaran resigned, triggering a sharp fall in Tata Group stocks, along with rising oil prices that spooked investors.At 1:57 pm, Sensex dropped over 550 points to trade below 77,600 mark, while the Nifty 50 lost over 150 points to trade below 24,300 level on Wednesday. The sharp losses wiped off more than Rs 2 lakh crore from the total market capitalisation of all BSE-listed companies, pulling it down to less than Rs 491 lakh crore.TCS, Tata Steel and Titan shares were the top losers on the Sensex, falling 2-5%. M&M, Infosys, Adani Ports and L&T shares followed, dropping 1-2%. SBI shares, meanwhile, bucked the trend to rise around 1%.Broader markets also slipped into the red, with the Nifty Smallcap 100 and the Nifty Midcap 100 indices falling around 0.3%. This came as the India VIX, which measures volatility in the market, inched 1% higher to 12.Among the sectors, the Nifty IT index tumbled more than 2% as heavyweight TCS shares crashed 5%. Nifty Consumer Durables, meanwhile, fell more than 1% to follow. The Nifty PSU Bank index, however, gained over 1.5%. The overall market breadth turned negative, with the NSE seeing 1,283 advances against 1,967 declines, while 95 stocks remained unchanged. Here are the key factors pushing the market down today. Tata Sons Chairman N Chandrasekaran resigns N Chandrasekaran on Wednesday resigned as Tata Sons Chairman after one board member did not support the proposal to extend his tenure. The Economic Times was the first to break the development this morning. Chandrasekaran’s current tenure as chairman of Tata Sons ends on February 20 next year.“Tata Sons is a very large institution and there are many strategic projects that are under critical stages of execution,” he said. “It is not only necessary to have a leader in place to lead the Group beyond Feb 2027, but also clarity on leadership is important for employees, investors, partners and other stakeholders… Under these circumstances, earlier today, I have communicated to the Tata Sons Board that I have decided not to offer myself for reappointment when my term ends,” he added.Following this, shares of the salt-to-airlines conglomerate Tata Group companies tumbled sharply, with heavyweight stocks including TCS, Titan and others pulling down overall market indices.TCS, which has the largest market capitalisation in the Tata pack, crashed around 5%. Titan and Tata Steel fell around 2% each, while Trent shares were down around 1%. Tata Motors Passenger Vehicles (TMPV) was down 3%, while Tata Consumer and Tata Power fell up to 2%.MORE TO COME...