DVAT and CST due date of filling return

Last date to file return under DVAT Act depends upon turnover of the dealer.
Turover Frequeny of return Time to file Manual return Electronic Return
0-10 lakh Yearly 75 Days N.A.
upto-50 Lakh Half Yearly 45 Days 42 Days
Upto 5cr. Quarterly 28 Days 25 Days
Above 5Cr. Monthly 28 Days 25 Days

Can u please tell me that turnover of which year will be considered for calculating taxable turnover, whether for c/y or p/y.