Five states – Rajasthan, Chhattisgarh, Jharkhand, Punjab and Himachal Pradesh – have informed the Centre that they would be reverting to the Old Pension Scheme. Some analysts even believe that one of the reasons for the Congress victory in Himachal was its campaign promise to revert to the Old Pension Scheme. At the same time, the Centre has warned that this move spells fiscal irresponsibility. Some economists have said it could even lead to a scenario of possible defaults on pension payments. But government employees in different states have staged protests demanding the Old Pension Scheme. So what exactly is the difference between the Old Pension Scheme (OPS) and the New Pension Scheme (NPS)? Why do employees want the OPS, while the Centre is pushing for NPS? Realistically speaking, is the OPS fiscally sustainable in the long run? Or will it bankrupt state governments?