 In a 2006 survey of carbon emissions in major UK cities conducted by British Gas, Southampton was ranked as being one of the lowest carbon-emitting cities in the United Kingdom.2016 mid-year population estimates suggests there are 254,275 people within the Southampton area.At the 2011 Census, the Southampton built-up area (which is a little larger than the area controlled by the City Council) had a population of 253,651.