According to B. B. Lal, former DG of ASI, Kalibangan site shows that an earthquake occured around 2600 BC, which brought to an end the Early Indus settlement at the site. It is perhaps the earliest archaeologically recorded earthquake.
The term ‘Aryan’ means ‘noble’. It was used as a self designation by Indo-Iranian people. It was used in vedic period i India as an ethnic label for themselves as well as to refer noble class.