Photo taken on June 23, 2016 shows the Rio 2016 olympic village in Rio de Janeiro, Brazil. Rio 2016 unveils athletes' village to mark Olympic Day on Thursday. (Xinhua/Li Ming)
Photo taken on June 23, 2016 shows the Rio 2016 olympic village in Rio de Janeiro, Brazil. Rio 2016 unveils athletes' village to mark Olympic Day on Thursday. (Xinhua/Li Ming)

RIO DE JANEIRO, July 4 (Xinhua) -- Tuesday will mark the start of the one-month countdown to the Rio 2016 Olympic Games as seven years of preparations reach their most critical juncture. Xinhua analyzes Rio's progress and identifies key challenges facing organizers ahead of the opening ceremony on August 5.

GAMES ORGANIZATION

Rio 2016 organizers have avoided many of the problems that beset the World Cup in Brazil two years ago, when most of the stadiums were running late amid huge budget overruns.

Last week city officials said that the construction of Rio's Olympic Park had reached 99% completion.

Five of the nine venues at the park are ready: Arena Carioca 1 (basketball), Arena Carioca 2 (judo, wrestling), Arena Carioca 3 (taekwondo, fencing), Future Arena (handball) and the aquatic center (swimming). Work on the athletes' village, media facilities and the Olympic Park hotel has also been completed.

Despite the encouraging progress at most Olympic facilities, not everything has gone to plan. Work is ongoing at the velodrome, a warmup pool at the Maria Lenk Aquatic center and two tennis courts.

City officials have said that the velodrome - the least advanced Rio 2016 venue - will be ready by mid-July, more than six months behind schedule.

POLITICAL CRISIS, RECESSION

In May, Brazil's senate voted to begin an impeachment trial against President Dilma Rousseff for her alleged manipulation of government accounts. A verdict is not expected to be given until after the Olympics, averting the threat of a major distraction from sport's showpiece event.

Political turbulence has coincided with a massive corruption scandal at state-run oil company Petrobras that has tipped Brazil into its worst economic recession in decades.

Rio has been among the states hardest hit by the crisis. Last month, governor Francisco Dornelles declared a state of financial emergency, saying public services faced "total collapse" and warning that commitments for the Games might not be honored.

Rio de Janeiro's city government and Rio 2016 organizers later eased concerns about the Olympics, saying the state's woes would not impact the Games.

CITY INFRASTRUCTURE

While swathes of Rio still resemble vast construction sites, many infrastructure projects slated for the Olympics are almost ready.

Asphalt for new express bus lanes to Olympic venues has been laid while a road featuring Brazil's longest underground tunnel - bypassing the city centre - has also been partially opened.

Refurbishment work at Rio's Tom Jobim international airport will also be concluded within days, officials have said.

But there is still doubt over whether a new metro line connecting the city to Olympic Park in Barra da Tijuca will be ready in time.

Some of the new stations are yet to open and engineers are still conducting tests along the 16km stretch of tracks. The state government has said the line will open on August 1, four days before the Games begin.

Laborers are also scrambling to finish a new tram line linking Rio's domestic airport to its major bus terminal, via the revamped port district.

Infrastructure concerns were heightened in April when an elevated bicycle track collapsed into the sea, killing two people.

SECURITY

Days after Dornelles declared a financial emergency, the federal government agreed toprovide the state with 850 million US dollars in emergency funds to guarantee security during the Games.

Brazil plans to deploy 85,000 soldiers and police during the Olympics, about double the number used at the London 2012 Games.

Earlier this year Rio's state government cut 550 million US dollars from its Olympic security budget, but denied the move posed a risk to safety.

In May, Dornelles issued a request for the federal government to deploy national armed forces in the city's streets as part of a 15,000-strong military contingent during the Games.

Brazil has also launched an awareness campaign designed to foil possible terror plots during the mega-event.

The initiative involves the distribution of brochures, posters and booklets explaining how to identify people engaging in suspicious activity.

In June the government said Brazil's intelligence agencies were working alongside counterparts in the United States, England, France, Israel and Russia to counter the threat of terrorism.

POLLUTION

Sailing's international governing body Word Sailing has said that it is satisfied with efforts to clean Rio's much-maligned Guanabara bay.

The city government last year admitted it will not be able to fulfil a 2009 pledge to reduce pollution in the bay by 80% before the Olympics.

But large nets that block the flow of waste into competition areas and eco-boats that scoop up trash from the water's surface will ensure the bay is fit for sailing, according to officials.

After his May visit to Rio, World Sailing CEO Andy Hunt said the bay's water quality was "noticeably better" within the Olympic sailing routes.

A cleanup operation at the the Rodrigo de Freitas lake has also eased pollution concerns for rowing and canoeing events, according to organizers.

LEGACY

Rio 2016 chief Carlos Arthur Nuzman has said that the Olympics will have the same transformative effect on Rio that the 1992 Games had on Barcelona.

Among the infrastructure projects that have coincided with the Games are a port revamp, tram and subway lines, roads and express bus services.

Meanwhile some Rio 2016 event venues will be turned into public schools, public sports facilities and leisure centers, according to officials.

But the immediate post-Games challenge for the city and state governments will be to recover Rio's financial health amid sinking tax revenue from the struggling oil industry.

Many providers of essential services like hospitals and police are on the cusp of collapse as public funds dry up and civil servants wait to be paid.