Dushanbe (Dyushambe until 1929, Stalinabad until 1961), is the capital and largest city of Tajikistan. Dushanbe means "Monday" in Tajik, and the name reflects the fact that the city grew on the site of a village that originally was a popular Monday marketplace.
sorry, I don't know for January. I don't even know if there is a Tajik word for January. Tajik being a language of the Iranian language group, I suspect that the Tajik words for months are those of the Persian calendar.