In order to save clean water, Ulaanbaatar streets are being washed with domestic and industrial water which has already been used – this is technically known as “greywater”. Special purpose street sweeper vehicles are using greywater from the Coca-Cola factory to clean the city’s streets and squares. Chinggis Sqaure is being cleaned with the greywater every Tuesday and Thursday, at 08.00-10.00 am. Depending on the traffic, roads are normally washed during the night time. The street sweeper trucks wash Ikh Toiruu, Baga Toiruu, Narnii Zam, Peace Avenue and Chinggis Avenue between 23.00pm and 06.00am.