Swanscombe is a small town in the District of Dartford in Kent, England. It lies east of Dartford and 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 concrete. The first concrete manufacturing 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 up a works at Swanscombe in 1825, utilizing chalk from Galley Hill, having patented a new cement called British Cement. The Swanscombe plant was consequently obtained by John Bazley White & Co, which came to be the biggest component of Blue Circle Industries when it formed in 1900. It finally shut down in 1990. Between 1840 as well as 1930 it was the largest cement plant in Britain. By 1882 numerous cement makers were operating across the north Kent area, yet the resulting dirt air pollution drove individuals of Swanscombe to take lawsuit versus the regional cement jobs. In spite of numerous technological innovations, the problem continued into the 1950s, with telegraph lines over an inch thick in white dust. Modern cement kilns in Kent using chimneys 170 m (550 feet) in height are now stated to be the cleanest worldwide. Nonetheless, the neighbouring Medway towns are reported to be one of the most polluted occupied location in the UK, as well as the concrete market contributes to acid rain in Scandinavia.