The mayor of the Colombian capital, Bogotá, has tried to reassure residents angry over a bin strike that the problem will be solved within 72 hours.
Mayor Enrique Peñalosa said that more than 3,750 tonnes of rubbish clogging the city would be cleared soon.
The build-up is due to a strike by bin collectors which started last Thursday.
Mr Peñalosa declared an environmental emergency a week ago but residents say the situation in some neighbourhoods has deteriorated since.
Many residents have taken to wearing masks to shield their noses from the stench wafting through the streets.
Workers for Aguas de Bogotá, the public company currently in charge of refuse collection in half of the capital, stopped work last week in protest at a looming change in the way contracts are awarded, which they fear will leave 3,200 employees out of a job as of 12 February.
While some of the 6,300 tonnes of rubbish produced in the city daily have been picked up by private firms, mountains of plastic bags remain piled up.
On Tuesday night, residents of the neighbourhood of Engativá, one of the worst affected, burned a bus during a protest against the situation.
Mayor Peñalosa is blaming his predecessor in the job, Gustavo Petro, for the problems with Aguas de Bogotá.
Mr Petro was sacked from his post in December 2013 for allegedly mismanaging the city's rubbish collection but was later reinstated after a court ruling.