Domestic stock markets suffered their worst day in three weeks on Thursday with benchmark indices snapping their longest gaining streak in nearly six years, as a record number of new COVID-19 infections in parts of Europe spooked investors across the globe. The Sensex index dropped 1,097.98 points - or 2.69 per cent - to 39,696.76 at the weakest level during the session, and the broader Nifty benchmark dropped to as low as 11,666.30, down 304.75 points - or 2.55 per cent - from its previous close. The rise in coronavirus infections across Europe and no sign of a vaccine anytime soon hit global market sentiment, according to analysts.