The WIll can be executed anywhere whether in delhi or uttarakhand for properties anywhere in India. If your father lives in delhi he can register the WIll in the sub-registrar office that has jurisdiction over his current residence and bequeath any and all properties anywhere in india to persons of his choice in that Will.
But you may also consider using a Settlement deed which he can register either with life interest (in which case it will come into effect only after his demise) or without life interest or immediate (in which case the property is yours after the registration). It would cost around +-25K (depending on state) for registering a settlement deed .....but it removes lots of hassles confusions that can occur after demise.