Indian stock markets experienced significant individual stock movements on the first trading day of the year, despite modest overall gains in the Nifty 50 and BSE Sensex. Vodafone Idea shares surged nearly 7% following promoter inflows and a revised liability settlement agreement. Conversely, tobacco stocks like ITC and Godfrey Phillips plunged up to 16% due to new government levies on tobacco products and pan masala, effective February 1. Other stocks such as Voltas and Adani Total Gas also saw sharp movements.