How to determine value of supplies in case of Rate of exchange of currency, other than Indian rupees under GST

Rule-34 of CGST rules 2017

34. Rate of exchange of cur­ren­cy, oth­er than Indi­an rupees, for deter­mi­na­tion of value.- 

The rate of exchange for the deter­mi­na­tion of the val­ue of tax­able goods or ser­vices or both shall be the applic­a­ble ref­er­ence rate for that cur­ren­cy as deter­mined by the Reserve Bank of India on the date of time of sup­ply in respect of such sup­ply in terms of sec­tion 12 or, as the case may be, sec­tion 13 of the Act.