Dhola Vira is dated ,at least, to about 4,500 years ago,according to Archeologist Sri. Bisht
The well deveoped structures and advanced water storing wells indicate a civilization which has been there for quite sometime.
The answer lies in the river Saraswathi.
This is the earliest reference to Vedic calendar with year beginning at Winter Solstice, found in Rigveda (5-77-1/2; 1-46-14; 7-69-3/2). Heliacal rising of Ashwini Nakshatra (Aries) can be seen to occur on 5th January, 7000 BC, marking the year beginning (Fig. 1)…The Sky of 19th December, 6000 BC at sunrise on the Winter Solstice day shows that Ashvini gave way to bright star Chitra (α Vir) on opposite side (Western horizon). A full Moon in Chitra Nakshatra provided a new time marker in the sky and heralded the lunar month naming system-Chaitra, Vaisakha etc. (Rigveda: 5-74-1,2 and Tait Samh. 7-4-8).