The Niti Aayog has roped in Crisil to undertake an evaluation of the fertiliser subsidy scheme, which accounts for 45% of the Centre’s budget outgo on major subsidies, to assess its efficiency and fiscal sustainability for policy intervention, sources said. Nutrient Based Subsidy (NBS) policy came into effect from April 1, 2010, for Phosphatic and Potassic (P&K) fertilizers. Under this, while the subsidy is meant to be fixed, in practical terms, the government has enhanced it, to insulate farmers from global price hikes of imported items. The urea subsidy scheme in India has been in place since the implementation of the Retention Price Scheme (RPS) in 1977; for long years, the issue prices to farmers have remained the same.