ONGC gets green nod for Rs 3,500 cr project in Assam The company proposes to carry out drilling in 100 locations to evaluate the hydrocarbon potential of 21 different onshore Petroleum Mining Lease (PML) blocks in a non-forest area covering 944.39 km in Assam and Assam Arakan Basin covering whole of the Upper Assam North in Sivasagar district.