Human rights groups say the unexplained deaths of thousands of migrant workers during Qatar’s nearly 12 years of preparations for the World Cup have tarnished the tournament, exposing lax oversight by soccer’s international governing body, FIFA, and abusive labor conditions in the host country.Qatar, the smallest country and first Arab state to host the tournament, has rebuffed calls for it, along with FIFA, to contribute to a compensation fund for deceased workers and establish an independent body to investigate their deaths.Qatari officials say the country has already provided tens of millions of dollars to workers whose wages were withheld by their companies.Migrant workers make up the vast majority of Qatar’s population, with many Nepali, Bangladeshi, Pakistani and Indian workers employed in low-wage jobs, including construction.Because Qatar’s death certificates often cited natural causes or cardiac arrest, it was generally difficult to prove how workers died, he added, even when family members or colleagues believed that “humidity or overtime work or mental stress” were to blame."