Eight riders pulled out overnight while one of the race favourites, the 2020 champion Tao Geoghegan Hart was stretchered into an ambulance following a nasty fall with suspected breaks to his leg and pelvis.
As the race resumed after Monday s rest day, Welshman Geraint Thomas of Ineos Grenadiers retained the pink jersey with no further changes in the top five since Remco Evenepoel quit the race Sunday night with COVID.
Magnus Cort of the Education First team won a rain-sodden 10th stage of the Giro d Italia on Tuesday after his escape group beat home the peloton on an eventful 196km run from Scandiano to Viareggio.
Giro d Italia organisers said Monday they were tightening COVID protocols after positive tests claimed a series of big-name riders, including leader Remco Evenepoel.
Race favourite Remco Evenepoel took back the overall lead of the Giro d Italia on Sunday, winning a rainy 35km stage nine individual time-trial by a single second from Geraint Thomas.