National Calamity Contingent Duty exemption for crude petroleum from specified production sharing fields and NELP exploration blocks. Exemption relieves petroleum oils and oils obtained from bituminous minerals, crude, produced in the listed production sharing fields or in exploration blocks offered under NELP through competitive international bidding, from the whole of the National Calamity Contingent Duty leviable under the relevant finance enactments, based on the Central Government's statutory power and its satisfaction of public interest.