India's Oil Ministry has instructed Reliance Industries, Royal Dutch Shell and ONGC to pay $3.8 billion as the increased share of the government's earnings from the Panna-Mukta and Tapti (PMT) fields after a UK court rejected challenges to the arbitration award that went against the companies. The liability is to be shared by the companies in proportion to their interests in the oil and gas fields in the Arabian Sea - ONGCNSE -2.59 % (40%), RILNSE 0.78 % (30%) and Shell (30%). According to the government, profit should be calculated after adding the marketing margins of the companies and that only the actual taxes paid could be counted as costs, not the notional rate mentioned in the contract. The government barred state owned ONGC from the arbitration, although the outcome of the proceedings would apply to the exploration company as well. The Ministry of Petroleum & Natural Gas then computed the liability of the three companies and directed them in May last year to pay the differential share of profit and royalty of $3.9 billion. The companies refused to pay, saying the award had been challenged in a UK court and the liability has not yet been quantified by the tribunal.