Big Blow to ONGC as Tamil Nadu Moves to Block Hydrocarbon Wells Amid Backlash and Election Heat
Reversal follows hours after state authority posted approval online, triggering political storm
The Tamil Nadu government has signalled it would cancel the environmental clearance granted to Oil and Natural Gas Corporation (ONGC) for drilling 20 onshore exploratory wells in Ramanathapuram district, after mounting resistance from political parties, activists, and farmers who warned of ecological damage and a breach of earlier assurances.
The U-turn came just hours after the State Environment Impact Assessment Authority (SEIAA), functioning under the Union Environment Ministry, posted the clearance online. The approval, dated March 11, allowed ONGC to drill wells up to 3,000 metres deep across a 1,403 sq. km block in the Ramnad sub-basin, near the sensitive Gulf of Mannar Marine National Park and several bird sanctuaries.
The announcement sparked a political storm, with opposition parties accusing the ruling DMK of duplicity and allies scrambling to distance themselves. State Finance and Environment Minister Thangam Thennarasu said Chief Minister M.K. Stalin had taken a “firm policy position” against hydrocarbon exploration. “Considering the interests of farmers and the general public, the Tamil Nadu government will not allow such projects either now or in the future,” he said, adding that SEIAA would be asked to revoke its approval.
The new Tamil Nadu Government Release reads out as –
The environment, climate change, and energy resources are interconnected and should not be ignored in any part of Tamil Nadu regarding the permissions for the hydrocarbon projects! The Honorable Minister Mr. Thangam Thennarasu announced on 20.02.2020 that the areas in the Cauvery delta region have been designated as Protected Agricultural Zone (PAZ) through the creation of a notification in 2020. Based on this notification, new exploratory studies on gas, oil, coal reserves, and the existence of railway resources have been initiated in specific areas of Thanjavur, Thiruvarur, Nagapattinam, Pudukkottai, and Cuddalore districts. Moreover, in the year 2023, this initiative has also been expanded to the Mayiladuthurai district. In this context, M/s. Oil and Natural Gas Corporation Ltd. (ONGC) has initiated a survey regarding hydrocarbon reserves in the Mannargudi area.
This area has been expanded for the Myladuthurai Oil and Natural Gas Corporation Ltd. (ONGC), which had applied for a study regarding the lithium reservoir at the site. In this context, the State Environment Impact Assessment Authority (SEIAA) has issued an environmental clearance to the Oil and Natural Gas Corporation Ltd. (ONGC). Following this, the State Environment Impact Assessment Authority has instructed Tamil Nadu to revoke the permit granted to ONGC. For the welfare of the people and the environment, any project related to lithium cannot be permitted in any region of Tamil Nadu, as affirmed by the steadfast statement of Tamil Nadu Chief Minister Mr. M.K. Stalin. It is emphasized that not only now but also in the future, no such projects will be implemented in any part of our state.
The controversy highlights the deep sensitivity around hydrocarbon exploration in Tamil Nadu, where earlier drilling plans in the Cauvery delta faced massive farmer-led protests and forced policy rollbacks. With Assembly elections due in early 2026, the quick clearance and its withdrawal have become a flashpoint for opposition attacks and a reminder of the DMK’s tightrope walk between development and populist environmentalism.
Activists and residents argue the wells would deplete groundwater and threaten agriculture in one of the state’s most fragile regions. Environmental collective Poovulagin Nanbargal called the clearance “an act to deceive farmers” and warned of fresh protests if ONGC tried to move forward. They also alleged procedural irregularities, pointing out that the approval was uploaded not on the Union Environment Ministry’s Parivesh portal but on an outdated website.
The proposed wells span six taluks of Ramanathapuram — Thiruvadanai, Mudukulathur, Paramakudi, Keezhakarai, Kadaladi and Ramanathapuram — as well as Devakottai taluk of Sivaganga district. ONGC had applied for clearance in October 2023, with each well projected to cost ₹33.75 crore. Even with the now-contested environmental nod, the company still requires a Petroleum Exploration License from the state industries department, which has not yet been granted.
