A wide variety of steps were taken to clean up the city of London in the 19th century. Some steps taken to clean up London during the nineteenth century were as follows: Attempts were made to de-congest localities, reduce pollution and landscape the city. Demands were made for new ‘lungs’ for the city, and some attempts were made to bridge the difference between city and countryside through such ideas as the Green Belt around London. Architect and planner Ebenezer Howard developed the principle of the Garden City, a pleasant space full of plants and trees, where people would both live and work. He believed this would also produce better-quality citizens. The London underground railway was built to carry people to and fro from the city. As a result, the population of the city became more dispersed. Rent control was introduced to ease the impact of the severe housing shortage.