Equity markets sustained huge losses on Friday as investor sentiments took a hit after new coronavirus variant was detected in South Africa.The 30-share Sensex closed 1,687.94 points, or 2.87%, below at 57,107.15. The Nifty 50 fell 2.91%, or 509.80 points, to close at 17,026.45.South African scientists have detected a new coronavirus variant, called B.1.1.529. On Thursday, the Centre had advised states and Union Territories to take note of the new variant and asked them to ensure rigorous screening of international travellers.The World Health Organisation has said it will determine at a meeting on Friday if the strain should be designated as a “variant of interest” or “variant of concern”.Only four sectoral sub-indices – Dr Reddy’s Nestle India, Asian Paint and Tata Consultancy Services – gained during the trading in the Sensex bracket. On Nifty, only Cipla, Dr Reddy’s, Divi’s Laboratories and Nestle India made advances while the remaining 46 sustained losses. “With the depth of winter fast approaching in the northern hemisphere, this renewed Covid-19 outbreak is clearly the biggest risk,” said Christopher Wood, global head of equity strategy at financial services firm Jefferies.