Asap 16 points list civilizations on the silk road.

Bactrians, Sogdians, Syrians, Jews, Arabs, Iranians, Turkmens, Chinese, Malays, Indians, Somalis, Greeks, Romans, Georgians, Armenians, and Azerbaijanis.

the causes of the dust bowls were severe droughts,   lands became dry and hard, temperature was higher than usual, hot and dry conditions killed crops, high winds. because of those factors, the winds kicked up dry soil and created clouds of dust.