Qatari companies used to operate a system called "kafala", under which they sponsored foreign workers to come to the country but then prevented them from leaving their jobs.Under pressure from groups such as the International Labour Organisation (ILO), Qatar's government abolished "kafala", but Amnesty International says companies still put pressure on labourers to stop them switching employers.However, the Qatar government said the total was misleading, because not all the deaths recorded were of people working on World Cup-related projects.However, the ILO believes this is an underestimate, because Qatar doesn't count deaths from heart attacks and respiratory failure as work-related - even though these are common symptoms of heatstroke, brought on from doing heavy labour in very high temperatures.It has compiled its own figures from government-run hospitals and ambulance services in Qatar, covering work-related deaths and accidents for World Cup projects."