Nps premium

Regarding National Pension Scheme (NPS):

In my case, the limit of 1.5 lakhs of deduction using section 80C is easily achieved with PF, LIC and NSC contribution. I have read somewhere that we can get additional deduction of 50k on taxable income by subscribing to NPS scheme. Could someone clarify if one needs to invest 2 lakhs premium in NPS on an yearly basis or 50k annual premium is enough to get this advantage?

Thanks