The highly advanced Indus Valley Civilization took roots around 3000 B.C. in what is now northwest India and Pakistan and collapsed around 1700 B.C. Since the Indus script has yet to be deciphered, the causes of its demise remain a mystery, though there is some evidence pointing to natural disasters. Signs of a gradual decline began to emerge in 1900 B.C., and two centuries later, most of the cities had been abandoned. Archeological evidence suggests an increase in inter-personal violence and in infectious diseases like leprosy and tuberculosis. Historians and archeologists believe that severe and long-lasting drought, and a decline in trade with Egypt and Mesopotamia, caused the collapse of this culture. Evidence for earthquakes has also been discovered. Sea level changes are also found at two possible seaport sites along the Makran coast which are now inland. Earthquakes may have contributed to decline of several sites by direct shaking damage, by sea level change or by change in water supply.