Swanscombe is a town in the District of Dartford in Kent, England. It is located east of Dartford as well as north-west of Gravesend, in the civil parish of Swanscombe and Greenhithe. At the 2001 UK census, the Swanscombe selecting ward had a population of 6,418. Swanscombe was essential in the early history of cement. The initial concrete production works near Swanscombe were opened at Northfleet by James Parker, around 1792, making "Roman cement" from concrete stone brought from the Isle of Sheppey. James Frost opened a works at Swanscombe in 1825, using chalk from Galley Hill, having patented a new concrete called British Cement. The Swanscombe plant was ultimately acquired by John Bazley White & Co, which ended up being the biggest component of Blue Circle Industries when it created in 1900. It finally shut down in 1990. In between 1840 and 1930 it was the largest concrete plant in Britain. By 1882 several cement suppliers were running across the north Kent region, yet the resulting dust air pollution drove individuals of Swanscombe to take legal action versus the regional cement works. Regardless of different technical innovations, the issue lingered right into the 1950s, with telegraph lines over an inch thick in white dust. Modern concrete kilns in Kent using chimneys 170 m (550 feet) in elevation are currently stated to be the cleanest in the world. Nevertheless, the adjoining Medway towns are reported to be one of the most polluted inhabited location in the UK, as well as the cement industry adds to acid rain in Scandinavia.