WHO was harnessed early by the UN. They were forbidden from releasing information without the express approval of the UN Nuclear agencies. WHO is trying to regain its autonomy and ‘right’ to speak freely but it has a ways to go.
Try to understand that countries with nuclear power defend their nuclear power. Hans Blix, head UN nuke expert, is on video tape explaining that he only accepted and reported 1/10 of the radiation reported by Gorbachev’s nuke experts. Gorby is on record responding in shock to that decision. Yes, the UN and WHO are more than willing to lie and distort. That’s why the link I provided points to a document by physicians who are pushing back against the GLOBAL denial of Chernobyl. That is the banner under the website you linked - ‘representing GLOBAL nuclear organizations and professionals’.
You think with the left wing enviro-wacko domination of the UN that they wouldn't do anything and everything to get rid of nukes if they could? Have you heard the UN say anything about Chernobyl lately? They CAN'T, because the science and the studies undeniably show that the predictions of the effects of Chernobyl were highly exaggerated.