The Dirac Medal is awarded by the International Centre for Theoretical Physics (ICTP) in Trieste, Italy, on the birthday of the late British physicist Paul A.M. Dirac, for significant contributions to theoretical physics. He is also the second Indian winner of the Dirac Medal; the first was string theorist Ashoke Sen in 2012. Dhar and his collaborators then developed the so-called Abelian sandpile model as a mathematical version of the sandpile idea. The ICTP Dirac Medal was established in 1985 to honor Paul Dirac, the British physicist whose equations helped lay the foundations of quantum mechanics. He is only the second scientist based in India, after string theorist Ashoke Sen, to receive the Dirac Medal.