Carlo Janka, Switzerland’s former giant slalom world champion and Olympic champion from 2010, will retire from skiing after home downhill races in Wengen this weekend, he said Thursday. The 35-year-old Janka has struggled for fitness in recent seasons, mainly with back problems, and has not raced since March 2021 when he finished 24th in a Saalbach-Hinterglemm downhill. Janka took his world title in 2009 and doubled his Olympic gold in Vancouver with the overall World Cup title a year later. He remains the last Swiss to take the overall crown but compatriot Marco Odermatt is well placed to emu…