 By the 1220s, supply from Central Asia had dried up and Gujarat was under control of hostile forces.In response to the lack of silver, Iltutmish introduced a new bimetallic coinage system to Northern India consisting of an 11 grams silver "tanka" and the billon "jital", with 0.25 grams of silver.The Dehliwala was devalued to be on par with the "jital".