This definition appears very frequently
Settlement is concentrated in river valleys and along canals, especially the Amu Darya, Syr Darya, and Zeravshan (Zarafšan) river valleys and the Kara Kum canal zone. The majority of the population is located in the relatively small area extending eastward from Bukhara through Samarkand to the Zeravshan and Fergana (Far?ana) valleys and along the upper Syr Darya and, on a branch of the Syr Darya, in Tashkent and its surrounding countryside. Rural population densities in these areas often exceed 200 people per km2, the highest in the USSR. Other notable areas of concentration are the lower Amu Darya valley just south of the Aral sea, in the Kara Kum canal zone between the Amu Darya and the Caspian, and in the Vakhsh valley of the Tadzhik SSR. On the other hand, great stretches of territory are uninhabited or very sparsely populated, especially the Kara Kum desert in the southwest between the Amu Darya and the Caspian Sea and the Kyzyl Kum desert between the Syr Darya and the Amu Darya, and the mountainous zones of the extreme south and east, including the Gorno-Badakhshan area of the Tadzhik SSR (Glavnoe Upravlenie Geodezii i Kartografii.