Customs duty exemption for specified petroleum operations imports conditioned on official certification and contract-linked eligibility. Exemption from customs duty is provided for a specified list of goods imported for petroleum operations under contracts involving the Government of India and designated oil entities; coverage includes whole customs duty and any additional duty for equipment such as seismic vessels, drilling rigs and components, helicopters, platforms and related process equipment, line pipes, pipe-laying vessels, pollution-control vessels, chemicals, stores and oil well cement. Eligibility requires a certificate from an officer not below the rank of Deputy Secretary in the Ministry of Petroleum and Natural Gas confirming the goods are required for the petroleum operations and imported under the specified contract.