% of cst for andaman

you have to follow the VAT/CSTrules applicable in your state, from where you are selling the goods,

they might have exemption for their own sales but for purchases, either they have to issue requisite declaration or pay the tax as per the sellers state vat rules. 

We are selling our product of Green Tea to Andaman Dealers,Customers, Retailers. What will be the CST rate applicable for that sale.We currently Charge CST @ 5 % of without C Form.

According to me, in Andaman and Nicobar VAT is not yet implemented, still Sales tax prevailing in the UT.

As you are billing from West Bengal to Andaman, if Andaman dealer is registered under CST Act, it can be against C Form i,e. 2% else local vat rate applicable in West Bengal needs to be charged.

Refer the link https://en.wikipedia.org/wiki/Value-added_taxation_in_India 

As of 2 June 2014, VAT has been implemented in all the states and union territories of India except Andaman and Nicobar Islands and Lakshadweep Island.

with regards,

Subramanya