The World Health Organisation said Tuesday that health risks outside the exclusion zone of the failed Fukushima Daiichi nuclear plant have not augmented, even though Japanese authorities upgraded the emergency. "The risk assessment for health hasn't changed outside the 40 kilometres zone... outside the 40 kilometres zone we do not believe that the risk is greater today than it was yesterday," said Gregory Hartl, spokesman for the UN health agency. Hartl also stressed that there is no one left in the exclusion zone, and that measures taken "appears to be enough" for the moment. Japan upgraded its month-old nuclear emergency to a maximum seven on an international scale of atomic crises Tuesday, placing it on a par with the Chernobyl disaster a quarter-century ago. The reassessment to a "major accident" with "widespread health and environmental effects" was based on the total radiation released, which officials said was one-tenth of the 1986 accident in the then Soviet Union.