The Tamil Nadu Pollution Control Board (TNPCB) has demanded ₹73.68 crore in environmental compensation from Chennai Petroleum Corporation Limited (CPCL) for the oil that flowed into Ennore Creek after Cyclone Michaung in December 2023. CPCL is contesting the amount, and the National Green Tribunal stayed the demand in March 2025 on condition of a part deposit, according to the company’s stock exchange disclosure.
Nearly three years on, fishing families in Ennore and the creek’s mangroves are still the subject of tribunal hearings. This explainer sticks to what official documents and court filings say: how the spill happened, what the state ordered, what relief was paid, and where the case stands.
What happened in December 2023
Cyclone Michaung brought very heavy rain to Chennai on 3 and 4 December 2023. Oil was reported on the water near CPCL’s south gate on 4 December, according to a fishers’ association filing before the NGT’s southern bench. It spread through the Buckingham Canal into Ennore Creek, the Kosasthalaiyar river and the sea.
The state Environment, Climate Change and Forests Department set up a technical team on 10 December. Its finding, set out in the TNPCB press release of 11 December, was that the oil came from CPCL’s premises, passing through guard ponds and stormwater drains into the canal, and that stormwater management at the refinery was inadequate. CPCL officials had initially pointed to other sources upstream, Citizen Matters reported.
What TNPCB ordered
Using its powers under Section 33A of the Water Act, 1974, the Board directed CPCL to:
- find and urgently clean up oil hotspots in the Buckingham Canal, Ennore Creek and nearby areas;
- make sure all pipelines and tanks, including those at secondary units, were leak-free;
- pay environmental compensation for the damage and compensation to affected families, including for lost livelihoods;
- commission a leak detection and repair study and a full mapping of the oil spread through a reputed technical institution;
- take steps to prevent a repeat, failing which operations could be suspended.
Business Standard reported the directions the next day.
Clean-up and relief
The state’s then Environment Secretary said the clean-up was finished on 20 December 2023, with 105.82 kilolitres of oily water and 393.5 tonnes of oily sludge removed, and that about 60 hectares of mangroves needed cleaning, Citizen Matters reported. Reporters still found oil on boats and mangroves the next day.
On 23 December 2023 the government announced relief of ₹8.68 crore for 9,001 families: ₹12,500 per family and ₹10,000 for each of 787 damaged boats. CPCL was to bear ₹7.53 crore of it. Fishers’ groups said the amount fell far short of their losses.
The compensation case
| Date | Step |
|---|---|
| 24 Oct 2024 | TNPCB report to NGT puts compensation at ₹73,68,00,906 |
| 23 Nov 2024 | TNPCB issues show cause notice to CPCL |
| 27 Feb 2025 | TNPCB orders CPCL to pay ₹73.68 crore |
| Mar 2025 | NGT grants interim stay |
The November 2024 disclosure said CPCL would contest both TNPCB’s figure and a related IIT Madras report. Under the NGT’s interim stay, CPCL had to deposit half of the environmental damage cost, which TNPCB had put at ₹38.24 crore, or about ₹19.12 crore, within four weeks, or furnish a bank guarantee. The stay would lapse automatically if it did not.
The science is also disputed. A study commissioned by CPCL from TERI found no significant oil slick or lasting damage to biodiversity. The fishers’ association told the tribunal its samples were taken 28 days after the clean-up began and missed the real damage. We could not find a final NGT ruling on the compensation as of 18 October 2026.
The ammonia leak and the wider picture
Weeks after the oil spill, Ennore faced a second emergency. Ammonia leaked from a sub-sea pipeline serving the Coromandel International fertiliser plant in late December 2023, and residents of nearby fishing villages were taken to hospital with breathing trouble. Deccan Herald reported that 52 people were hospitalised. The state government ordered the plant to shut temporarily, The News Minute reported.
A technical committee examined the leak. The government accepted its report, which recommended a set of measures including legal action against the company, Deccan Herald reported, and the unit was told to meet a list of conditions before it could run again. A state minister later said the company had agreed to pay ₹5.92 crore in compensation, according to the same paper. The National Green Tribunal subsequently allowed the plant to reopen once it had obtained the required clearances, DT Next reported.
Together, the two incidents put the spotlight back on the Ennore-Manali belt, where refineries, fertiliser and power plants sit beside fishing villages and a tidal creek that drains floodwater from north Chennai. For residents:
- If you see an oily sheen, smell gas or see fish kills, call the state emergency line 112 and inform TNPCB’s district office.
- Fishers seeking relief or compensation should keep boat registration and loss records and approach the Fisheries Department.
- Track the NGT southern bench cause list for O.A. 180 of 2023 for the next hearing.
This is general information, not legal advice; affected families should consult a lawyer on claims.
Quick answers
Who caused the Ennore oil spill?
A state technical team concluded the oil came from CPCL’s premises. CPCL contests the compensation demanded.
How much compensation has TNPCB sought?
₹73.68 crore, which the NGT stayed in March 2025 on a part-deposit condition.
What relief did fishing families get?
₹12,500 per family for 9,001 families, plus ₹10,000 per damaged boat.
What happened with the ammonia leak?
Ammonia leaked from a sub-sea pipeline linked to Coromandel International in late December 2023. The company agreed to pay ₹5.92 crore in compensation, a state minister said.
Is the oil spill case over?
No final NGT ruling was found as of 18 October 2026.
Information checked against official sources on 18 October 2026. Fees, dates and rules can change; confirm on the linked official pages before acting.
Sources
- Press release on Ennore oil spill directions to CPCL, 11 Dec 2023 (Government of Tamil Nadu / TNPCB)
- CPCL disclosure on TNPCB show cause notice, 23 Nov 2024 (NSE)
- CPCL disclosure on TNPCB order and NGT stay, 20 Mar 2025 (NSE)
- Submission by applicant in I.A. 57 of 2024 in O.A. 180 of 2023 (National Green Tribunal)
- Oil spill in Ennore brings fishing to a standstill (Citizen Matters / Mongabay, Jan 2024)
- TN Pollution Control Board issues directions to CPCL on Ennore oil spillage (Business Standard, Dec 2023)
- Ammonia gas leak in Chennai’s Ennore leaves 52 people hospitalised (Deccan Herald)
- Chennai ammonia gas leak: TN govt shuts Coromandel International Ltd temporarily (The News Minute)
- Ammonia leak: Tamil Nadu govt accepts technical committee report on slew of measures including legal action (Deccan Herald)
- Ammonia gas leak: fertiliser company agrees to pay Rs 5.92 cr compensation, says Tamil Nadu minister (Deccan Herald)
- Ammonia leak incident: NGT allows Coromandel Intl Ltd to reopen Ennore plant after getting clearance (DT Next)
