The city has continued to grow during the 1990s to 2000s, its population rising from below nine to above ten million. Mason and Nigmatullina argue that Soviet-era urban-growth controls (before 1991) produced controlled and sustainable metropolitan development, typified by the greenbelt built in 1935. Since then, however, there has been a dramatic growth of low-density suburban sprawl, created by heavy demand for single-family dwellings as opposed to crowded apartments. In 1995–1997 the MKAD ring road was widened from the initial four to ten lanes.