The development of the coal fields of Kuznetsk Basin, (sometimes called the "Kuzbass") transformed the Siberian steppe. The south sector of the Trans-Siberian Railway became a great industrial center because of the activity surrounding the coalfields. These ancient reserves of 13,000,000,000 tonnes grew to 450,658,000,000 tonnes. In 1937, the 50 mines in this area produced a total of 17,300,000 tonnes. The coal production of this zone was comparable with that of all of British India, and half of that produced by Japan. Kuznetsk coal was the best in the USSR, with high energy and low sulphur content. The total anthracite reserve was 54 million tonnes; and was used in the Ural-Kuznetsk Metallurgical Combine. Siberia is also the coldest winters to survive, this includes freezing temperature such as -50 degrees.