is it compulsory for getting GSTIN no if the turnover is below 20 lakhs rupees.

No...... if aggregate turnover is below 20 lakhs........

my client is a owner of small restaurant (snaks / fast food). he is not liable to pay tax under income tax because his income is below 2,50,000.

now if he registers voluntarily under GST then as per the rules he is liable to pay GST on all sale transactions. (20 lacs exemption not available once a person gets registered under GST)

So question is

Q1. whether it is beneficial to register voluntarily under GST or should he enjoy basic exemption of 2.5 lacs under income tax?

Q2. whether he is liable to pay tax under both acts? income tax and also under GST? filing of return and payment of taxes under both the acts will be hardship for him.

so should he register voluntarily or not?