BUZZ-Vodafone's India unit tanks after court snub

(Updates with more information)

** Shares in India's No. 2 telecom firm, Vodafone Idea , down ~17% at 3.75 rupees

** India's Supreme Court slams mobile carriers for non-payment of billions of dollars in government dues, threatening them with contempt proceedings if they did not pay up by March 17

** Over 1 bln Vodafone Idea shares change hands, the stock's 5th busiest day ever; Sessions in which 1 bln or more shares were traded have all occurred in the last three months following the Supreme Court upholding the govt's demands in October

** VODA is saddled with about $3.9 billion in overdue payments, the biggest portion of the industry levy; Its Chairman Kumar Birla has warned the company may "shut shop" if it doesn't get relief

** Co on Thursday posted a bigger loss, its sixth straight quarterly loss, and maintained there was uncertainty about its ability to continue as a "going concern"

** VODA shares, once trading at a peak of over 120 rupees in 2015, hit a record intraday low of 2.40 rupees in November (Reporting by Nallur Sethuraman, Sachin Ravikumar in Bengaluru)