“Today, the Bogotá Metro has been guaranteed,” announced Mayor Enrique Peñalosa at an October 3 press conference. The bold statement came on the heels of two proposals for an elevated Bogotá metro, which if completed, will be one of the largest infrastructure projects in the city’s history. Bogotá’s current leader made this promise just four weeks before the next mayoral election, after which he will cease to be in power.

Two international private consortiums have submitted bids for the US$3.9 billion, 24-kilometer elevated line, and city officials have promised to complete a system meant to complement and not replace the existing TransMilenio articulated bus network. In a contested election all four mayoral candidates recognize the need for an improved mass transit system, but they differ in their approach. In these details lie enormous concerns over costs, timeline and environmental impact, all of which will affect the lives of commuters.

“One of Bogotá’s biggest problems is air contamination,” announced Claudia López in a Facebook video and during which the Alianza Verde mayoral candidate walks through the TransMilenio station at Calle 72, which she claims happens to be one of the most polluted in the city. Volunteers compare air quality measurements inside and outside the station. They find an astounding difference: the air inside the station appears to be six-times more contaminated than the air across the street.

The video demonstrates what each candidate has separately claimed: Bogotá’s transit system, including its aging non-electric buses, contribute significantly to pollution. The contamination also has a profound impact on the health of the traveling public. According to a 2019 study by the World Health Organization (WHO), TransMilenio commuters are exposed to dangerous levels of contaminants, and therefore have higher risks of contracting respiratory and cardiovascular illnesses.

Citing high bus emissions, López opposes any Transmilenio expansion. In a separate campaign video, she states: “Transmilenio is not, and never will be, a substitute for the metro.” Instead, she advocates for a full investment of transportation funds into a “clean air” metro system that runs from Suba to Engativá, in addition to the primary route along the Caracas corridor, and two regional routes from the North and South of the city.

In contrast with his center-left opponent, Carlos Fernando Galán, of Bogotá para la Gente, supports adding new TransMilenio routes to the Carrera Séptima, Avenida Calle 68, Avenida Boyacá, and Avenida Ciudad de Cali. The candidate, who has climbed steadily in the polls since joining the race, also addresses environmental hazards. According to the think tank AlCentro, the Carrera Séptima is one of the most congested roads in the nation and adding a fully electric and sustainable TransMilenio route could lead to cleaner air.

After Peñalosa’s announcement, Galán voiced full support for the Metro, but in the past, he has shared his concerns over financing. “I will do a metro that is financed, has financing from multilateral banks, has approval from the national government, and is ready for contracting. This is the metro I will do,” Galán stated in a radio interview with RCN.

Like Galán, Miguel Uribe Turbay of Avancemos also favors expanding TransMilenio with “clean technology” and replacement of SITP buses with newer, more environmentally-friendly models. As Mayor Peñalosa’s former General Secretary-General, Uribe has plenty of experience when it comes to understanding the city’s mobility priorities and worked closely with the district’s metro planning team. The 33-year old independent candidate has promised to deliver the elevated Metro with the first line along Caracas, and second extending from the locality of Suba to Engativá.

Hollman Morris of Colombia Humana is the only mayoral candidate who fully opposes the elevated metro for Bogotá. The former journalist and close political ally of former mayor Gustavo Petro claims that Peñalosa’s elevated metro is mired in corruption and has circumvented the required feasibility studies. Instead, the candidate proposes an underground metro that would run on electric, renewable energy, which he argues, reduces carbon emissions. In a similar stance with that of López, Morris opposes any expansion of TransMilenio should he be elected.

The submission of the bids indicates Bogotá is closer to achieving a long-awaited metro. The final contractor will be announced on October 21 and just six days before the election. According to the terms of the contract, construction must start early 2020, unless the new mayor decides to derail the plan.