CHENNAI: The State Environmental Impact Assessment Authority (SEIAA) has issued a notice to the Oil and Natural Gas Corporation Ltd (ONGC), seeking an explanation on why the environmental clearance granted for a hydrocarbon-related study in Ramanathapuram district should not be withdrawn.

The SEIAA had earlier granted ONGC clearance to carry out an environmental impact study on hydrocarbon reserves in Ramanathapuram. The move drew strong objections from environmental activists and fishermen. Quickly stepping in control the damage, Finance, Environment and Climate Change Minister Thangam Thennarasu urged the authority to rescind the approval, citing its inconsistency with the Protected Agricultural Zone (PAZ) Act.

Acting on the minister's intervention, the SEIAA has now formally sought a response from ONGC before taking a final decision on whether to cancel the permission to conduct the environmental impact study.

The Tamil Nadu government had declared the Cauvery Delta region a Protected Agricultural Zone (PAZ) through legislation enacted on February 20, 2020. This was brought in by the then AIADMK government after its decision to sign an MoU with CPCL to set up a greenfield refinery in Nagapattinam triggered anger across the Delta region.

Under the legislation, new exploration and mining activities for fuel, natural gas, coalbed methane, and shale gas have been prohibited in Thanjavur, Tiruvarur, and Nagapattinam, besides select areas in Pudukkottai and Cuddalore. The restriction was further extended to Mayiladuthurai in 2023.