The Rio Olympics is shaping up to be the most pivotal of recent times.

Not because the sporting action is any more anticipated than at previous Games - far from it - but because the Olympic concept has taken so many knocks in recent years that the very credibility of the Games is under threat.

In fairness, there has been criticism in the build-up to all Olympic Games in recent memory. This happens ­largely ­because the hordes of international ­media are on site days before the Games kicks off and have to file daily stories with little or no sporting action to discuss. But the build-up to Rio seems worse than normal.

Locally, health has been a big concern with the Zika virus seeing a number of high-profile withdrawals - mostly notably the top four male golfers in the world - even though the official line from the IOC has been that there is nothing to worry about.

Additionally, the water in the bay in which some of the athletes will be swimming has been criticized for being filthier than swimming pool. More ­recently, the sub-standard accommodation has been a favorite target - as it was in Sochi two years ago.

Safety has been another big area of concern, with the localized fears of kidnapping, robberies and scams added to the wider global threat of terrorism.

Unusually, perhaps, Chinese athletes - and fans - have also been complaining on social media, with some joking that the athletes' biggest challenge will be simply to return home alive.

But the pressure has been building on China's athletes and officials alike, with Liu Peng, head of China's Olympic Committee, saying that the country will face sterner competition in some of the disciplines it traditionally dominates. China will still, no doubt, see success in diving, gymnastics and some of the other sports Liu mentioned, but his comments prove that - in China as elsewhere - funding has to be justified by medals.

But it is the issue of doping that has arguably created the biggest cloud for Rio.

By refusing to issue a blanket ban on Russian athletes for state-sponsored ­doping, the IOC has transferred the ­burden to individual sporting federations. While arguing that this is somehow more fair to those affected, the result has done nothing to repair the damaged reputation of the Olympics.

Athletics - the showpiece event of the Games - already has its credibility in tatters. If these Games fails to win over sports fans from around the world, the Olympics may lose its relevancy forever.

The author is a Beijing-based freelance writer. dreyermark@gmail.com