Gst of pli comes under 80C or not?

I am assuming that 'pli' in your query is 'personal life insurance' (such abbreviations without explanation may be avoided on open forum). Text of Sec 80C(2)(i) that allows LIP (life insurance premium) is:  

(2) The sums referred to in sub-section (1) shall be any sums paid or deposited in the previous year by the assessee—(i) to effect or to keep in force an insurance on the life of persons specified in sub-section (4);

Law mentions 'any sum' & not 'premium', hence interpretation is that GST included in LIP is allowable as deduction u/s 80C. This is only an interpretation, so kindly take further professional advice before claiming full LIP including GST.