Krishi kalyan cess- payment to builder

I purchased the property, assuming the value is 20 Lakhs and all dues were settled during FY 2015-2016 except final settlement of 1 Lakh which was paid on September 2016. Builder is asking me to pay KKC @ 0.5% on entire 20 Lakh to get the possession letter. I occupied the flat in FY 2015-16 itself. Is builder's claim tenable? What are the options available for me to get the possession letter? Please provide an explanantion.