Pollution levels in Wigan mean the air is often too dangerous to breathe, according to the World Health Organisation.
An increased exposure to fine sooty particles in the atmosphere has seen the borough join a list of more than 44 locations across the UK failing quality tests carried out by the global body.
Scientists from the WHO believe that the level of fine particles, known as PM2.5s, as they measure less than two-and-a-half microns, should only be 10mg per cubic metre of air on average.
But the amount for Wigan was registered at 13, the same rate as Manchester but slightly under the readings for neighbouring Warrington at 14 and less than Salford, where the average reading was 15.
However Wigan does score better against another indicator, for PM10s, a slightly larger sooty particle, which while considered less of a hazard than PM2.5s, is still harmful to health.
The WHO recommended guideline for towns and cities is 20mg, per cubic metre, and the borough’s rating is 18.
Dr Toby Hillman, one of the WHO study’s leaders, from the Royal College of Physicians, said: “There isn’t a safe limit for the amount of pollution that’s been defined as yet and we know the effects of poor air quality run from cradle to grave. It’s a lifetime threat to human health.
“This is a really direct and tangible impact on UK health from the drivers of climate change, and taking action on air quality should be a priority.”
It has been acknowledged that the WHO guidelines are much more stringent than the European Union air quality guidelines, which allow for average PM2.5 levels of 25.
But experts say that the WHO limits represent a “safer threshold” for the public.
Dr Penny Woods, chief executive of the British Lung Foundation, said: “This study reveals the tragic reality that the most polluted areas are exactly where our most vulnerable are - schools, hospitals and clinics.
“The extent of the public health emergency we are facing demands nothing less than urgent action to protect our lung health.”
Earlier this year Public Health England linked 153 premature deaths in Wigan to air pollution. This was the second highest level in the North West behind Manchester.