As Rio de Janeiro prepares to host the world for the 2016 Olympic Games, the lead-up to the global sporting event has already faced its fair share of controversy. The timer now stands at six months for organizers to address the concerns.

Back in 2014, International Olympic Committee vice-president John Coates called the preparations for the Games the "worst" he's ever experienced.

Much has changed since then, with organizers working to address concerns that earned that scathing review. But a number of new challenges have emerged in more recent years.

With half-a-year to go to the opening ceremony on Aug. 5, here's a rundown of five controversies surrounding the Rio Olympics:

Zika virus

Recife Brazil Jan 26 2016 Aedes aegypti mosquitos

The outbreak of the Zika virus, carried by Aedes aegypti mosquito, was declared a public health emergency by the World Health Organization earlier this week. Olympic organizers are fighting to combat the virus ahead of the Games, scouring venues daily. (Mario Tama/Getty)

The latest controversy weighing on the Rio Olympics — not to mention the rest of Brazil — is the spread of the Zika virus, which was declared a public health emergency earlier this week. 

An outbreak of the mosquito-borne virus that is sweeping across the Americas has been centred in Brazil.

Zika has also been tentatively linked to a birth defect called microcephaly, characterized by infants born with abnormally small heads. This could affect travel to the Games, as women who are pregnant, or planning to get pregnant, are being advised to stay away from Zika-stricken countries.

In an attempt to the address the alarm raised by the Zika virus, officials are checking Olympic venues daily for mosquito-breeding grounds. They've also said the virus should be less of a problem come August, as Brazil's dry season should lead to fewer mosquitos.

On a national level, the Brazilian government plans to send troops door-to-door to help combat the mosquitos that carry the Zika virus.

Troubled waters


Some athletes fell ill after competing in test events held in Rio's polluted water, though a Canadian official suggests quality concerns are 'overblown.' (Matthew Stockman/Getty Images)

Tests conducted by The Associated Press last July showed Rio's Olympic waters were heavily polluted with human sewage, and an alarming number of disease-causing viruses and bacteria were present.

Some athletes fell ill last year when competing in water-based test events.

In its Olympic bid, Rio organizers pledged to clean up the city's water with improved sewage sanitation. But Brazilian officials have acknowledged the water will not be as clean as originally planned.

Still, Rio has not been idle on the issue. A new sewage facility has been built at the Marina da Glória, where Olympic sailing events will be held.

In December, Canada's chief medical officer, Bob McCormack, said the water concerns in Rio were overblown and Canadian athletes were well educated on how to avoid the risk of getting sick while travelling.

"I wouldn't drink the water out of the [lagoon]. No one should," said McCormack. "That's different than the risk of being on top of the water and getting splashed."

Building the Games

Rio venues

Despite previous concerns that construction for Olympic venues were behind, most now stand pretty close to completion. (Rio 2016 Olympics Twitter photo)

In the years leading up to the Games, concerns have been raised about whether Rio's Olympic infrastructure would be ready on time. 

Those fears were carried over, in part, from when Brazil hosted the 2014 FIFA World Cup. Prior to the World Cup, the country fell behind on the construction of the soccer stadiums, though the venues were ultimately delivered on time.

Last May, Reuters reported only 10 per cent of 56 Olympic construction, overlay and energy projects were finished.

But progress has improved since then. Marking the one-year countdown to the Olympics, Rio Mayor Eduardo Paes announced all Olympic venues would be delivered on time for the Games, a feat he referred to as "a miracle."

Slumping economy


Brazil's worst recession since the 1930s is already hitting the 2016 Games, with the operating budget slashed by about 30 per cent. (Rodrigo Abd/Associated Press/File)

Brazil is also in the midst of an economic crisis, facing its worst recession since the 1930s.

Budgets — including that of the Olympics — are getting slashed. Olympic organizers are trying to find much-needed savings, looking to cut about US $530 million from the $1.9 billion operating budget, or about 28 per cent.

Proposed cuts have included reducing food and travel costs for Olympic officials. At one point, organizers were considering charging athletes for air conditioning, though that was later reneged.

Brazil's economy was booming when the 2016 Summer Olympics were awarded seven years ago. But the real has since lost a third of its value, the country's GDP has tumbled, inflation has risen above 10 per cent, and unemployment sits around 9 per cent.

Political scandal

Brazil Protest

Recent scandals have led to protests demanding the impeachment of Brazilian President Dilma Rousseff. (The Associated Press)

The economic hardship of Brazil has been accompanied by a political scandal that extends all the way to the country's top office.

A congressional committee is considering impeachment of Brazilian President Dilma Rousseff for allegedly violating budget laws to increase spending during her 2014 re-election campaign. 

Rousseff and the Brazilian government have also struggled with the state-run oil company Petrobras, which has been mired in a massive corruption scandal. Allegations include political kickbacks, price-fixing and bribery.

The Rio Games have not escaped the impact of the corruption. Several major Brazilian construction firms responsible for the majority of Olympic infrastructure projects have also been implicated in the scandal.