In late November 2011, after a series of tremors in Idukki district, Kerala's parties united behind a demand to replace the 116-year-old Mullaperiyar dam, which Tamil Nadu operates under an 1886 lease. Hartals, fasts and a 208 km human chain in Kerala were met by mass marches in Tamil Nadu's Theni district, and the Kumily border was effectively shut for about two weeks as people and property were attacked on both sides. In May 2014 the Supreme Court found the dam safe, struck down Kerala's 2006 law capping the water level at 136 ft and allowed Tamil Nadu to raise it to 142 ft. Kerala still wants a new dam, and a fresh safety review was under way in September 2026.
Key takeaways
- The Mullaperiyar dam is in Kerala's Idukki district but is run by Tamil Nadu; Kerala says it is unsafe and wants a new dam, Tamil Nadu says it is safe and wants a higher water level.
- After tremors in 2011, Kerala saw hartals, legislators' fasts, a 208 km human chain and a unanimous Assembly resolution for a new dam in late November and December.
- In Tamil Nadu's Theni district, farmers blockaded the highway and marched on Kumily; Malayali-run shops and houses were attacked in Tamil Nadu, and Tamil workers were attacked in Kerala.
- The Supreme Court's Empowered Committee found the dam safe, and on 7 May 2014 the court struck down Kerala's 2006 law and allowed the level to rise to 142 ft.
- In 2026 Kerala still sought a new dam, Tamil Nadu still rejected it, and an expert safety review was under way.
Background: a dam in Kerala run by Tamil Nadu
The dam was built across the Periyar in Idukki under an 1886 agreement between the Maharaja of Travancore and the British government. Tamil Nadu operates and maintains it on a 999-year lease, and its water irrigates rain-shadow districts including Theni, Madurai, Dindigul, Sivaganga and Ramanathapuram Tribune Onmanorama.
On 27 February 2006 the Supreme Court allowed Tamil Nadu to raise the water level from 136 ft to 142 ft. Within weeks Kerala amended its Irrigation and Water Conservation Act, listing the dam as endangered and fixing its level at 136 ft. Tamil Nadu sued, and in 2010 the court set up an Empowered Committee under former Chief Justice A S Anand LiveLaw Deccan Herald.
How it started: the tremors
How many tremors hit the area in 2011 was itself disputed. Claim · Kerala Kerala government statements spoke of 22 tremors in four months, and the LDF said 28 tremors in nine months had left the dam "shaky" Frontline IANS via Ummid. Congress MP P J Kurien told the Rajya Sabha that an IIT Roorkee study said the dam could collapse in an earthquake above magnitude five Tribune.
Claim · Tamil Nadu AIADMK MPs called the figure of 22 tremors "blatantly false" and said IMD data showed four mild tremors that year. Jayalalithaa said the 18 November tremor "did not even have an iota of impact on the dam" Frontline. Tamil Nadu banned the film Dam 999, about a dam collapse, on 24 November.
The campaign in Kerala
On 28 November the ruling UDF and the opposition LDF jointly shut Idukki district, with shops closed and vehicles off the roads. Kerala MPs from all parties held a sit-in at Parliament. Legislator Roshy Augustine began a satyagraha in Thiruvananthapuram, and CPI legislator E S Bijimol of Peerumedu was on an indefinite fast Khaleej Times Oneindia. Four Tamil Nadu MPs held a counter-protest Gulf Times.
On 29 November the BJP shut Idukki, Kottayam, Alappuzha and Ernakulam, and the Kerala Congress (Mani), a UDF member, added Pathanamthitta. BJP workers blocking the Kumily check post clashed with police Gulf News Deccan Herald. On 3 December Youth Congress volunteers marched to the dam, and on 4 December BJP workers went there with an earth mover and tried to open a channel at the baby dam Frontline.
On 8 December the LDF formed a 208 km human chain from Vandiperiyar, near the dam, to Marine Drive in Kochi, with V S Achuthanandan and Pinarayi Vijayan taking part Deccan Herald. On 9 December a special session of the Kerala Assembly unanimously resolved that a new dam must replace the old one Tribune. An all-party meeting kept the demand to cut the level to 120 ft and appealed for no violence Gulf News.
The border: Kumily, Gudalur, Cumbum and Theni
On the evening of 5 December an unidentified gang attacked a vehicle carrying Tamil plantation workers at Kumily. Crowds then picketed the Theni-Kumily highway at Gudalur, Kambam (Cumbum) and Lower Camp for nearly 24 hours, attacked cafes and shops run by Malayalis and stoned Kerala-bound vehicles. Prohibitory orders were imposed in Kumily and the Tamil Nadu villages of Kambammedu and Bodimettu. Farmers' unions in five districts stopped vegetables, milk and other goods going to Kerala Gulf News.
On 11 December, police said, about 10,000 protesters gathered on the Tamil Nadu side of Kumily. After a man said he had been attacked in Kumily, the crowd threw stones at people on the Kerala side, who retaliated. The lathicharge that followed left 50 injured, cases were registered against more than 10 people, and protesters threw slippers at Tamil Nadu Finance Minister O Panneerselvam PTI via Tribune Deccan Herald. On 12 December Tamil Nadu police again used lathis to stop a march on Kumily. Gulf News reported that protesters stoned several houses and damaged property of Malayali families Gulf News.
By 13 December Theni district was in its fourth day of protests: buses stopped after eight were stoned, a bakery burned in Andipatti and schools shut PTI via Tribune. Kerala, which gets nearly 70 per cent of its vegetables, milk, meat and eggs from Tamil Nadu, saw prices rise Gulf News.
On 18 December about 20,000 farmers rallied in Gudalur and 15,000 in Cumbum, peacefully, according to The Hindu. They carried a mock funeral bier for Oommen Chandy and V S Achuthanandan, and Gudalur's shops stayed shut for the 11th day The Hindu. By then 286 Tamil plantation workers, 120 of them women, had come back from Kerala after alleged attacks, and buses had not run via Kumily for 13 days PTI via Governance Now.
Timeline
Hartals in Kerala
Idukki shuts on 28 November, and five districts on 29 November Gulf News.
Violence on the border
Tamil workers' vehicle attacked at Kumily, then the highway is blockaded in Tamil Nadu Gulf News.
Supreme Court urges restraint
Constitution Bench keeps the level at 136 ft and refuses Kerala's 120 ft plea Tribune.
Leaders meet the PM
Jayalalithaa and Karunanidhi meet Manmohan Singh in Chennai; over 750 DMDK protesters detained Tribune.
Both accounts
Kerala's account
Oommen Chandy said he was not against giving water to Tamil Nadu, but the dam was frequently hit by tremors and a new one was needed Tribune. Speaking of the safety of three million people, he asked why Jayalalithaa, who opposed the Koodankulam nuclear plant on safety grounds, would not apply "the same yardstick" Tribune. On 18 December he assured Panneerselvam that Tamil-speaking people in Kerala would not be affected Tribune.
Tamil Nadu's account
Government's position Jayalalithaa said the dam was "well maintained and periodically reinforced" and that doubting it because it was 116 years old was "sheer ignorance" Frontline. Tamil Nadu parties saw the new dam as a way for Kerala to take control of the water. She also told her farmers this was not a quarrel with the people of Kerala and urged them not to harm Keralites or their property Deccan Herald.
The DMK told the Prime Minister that Kerala's campaign had "forced Tamils living in Kerala to leave that state" PTI via Tribune. No full count of attacks or arrests by either government appears in the sources reviewed. Later reporting said several people and vehicles were attacked on both sides Arab News.
The Centre and the Supreme Court
On 23 November Union Water Resources Minister Pawan Kumar Bansal said water was a state subject and "there is no power with Government of India to impose any decision of its own" Deccan Herald. On 17 December Home Minister P Chidambaram called Kerala's fears "unnecessary" and linked them to "bypoll fear", then withdrew the remark a day later Tribune Tribune.
The Prime Minister told Tamil Nadu Congress MPs he was "very much worried" over the violence. The Centre invited officials from both states, but Tamil Nadu stayed away from the meeting Tribune Tribune. On 13 December a five-judge bench under Justice D K Jain said both states were "adding fuel" to the fire instead of putting it out. Two days later the Centre told the court it could not deploy the CISF without Kerala's consent. Tamil Nadu also rejected a meeting of chief ministers Tribune.
Both the parties instead of dousing the fire are adding fuel to it. There has to be sanity and sensitiveness.
Supreme Court Constitution Bench, 13 December 2011 (PTI via Tribune)
The Empowered Committee filed its report on 25 April 2012. According to sources quoted by PTI, it found the dam safe on "hydrologic, structural and seismic considerations" and said the level could go back to 142 ft. It also said Kerala should reconsider the new dam, which it could build at its own cost if cleared Deccan Herald.
The 2014 verdict
On 7 May 2014 a Constitution Bench led by Chief Justice R M Lodha declared Kerala's 2006 amendment unconstitutional in its application to the dam. It held that a legislature could not override a court decree, and barred Kerala from stopping Tamil Nadu raising the level to 142 ft The Hindu. It found no "drastic change in circumstances" to reopen the safety question. A new dam would need both states to agree, and a three-member supervisory committee chaired by the Central Water Commission was set up The Hindu LiveLaw.
Jayalalithaa called it "a historic victory". Theni farmers set off fireworks, and in Kerala the Mullaperiyar Samara Samithi and the UDF called shutdowns Arab News. On 9 June the Kerala Assembly passed its fourth unanimous resolution for a new dam The News Minute. The level reached 142 ft on 21 November 2014 Deccan Chronicle. On 2 December the court dismissed Kerala's review petition, which argued that the committee's test data had not been shared with it The News Minute.
Outcome
- Deaths: None reported in the sources reviewed.
- Injuries: 50 hurt in the 11 December lathicharge at Kumily, per police. No overall count was published.
- Cases and detentions: Cases against more than 10 people after the Kumily clash. More than 750 DMDK members detained and released on 26 December, and Seeman and 300 Naam Tamilar supporters arrested at Walayar.
- Displacement: 286 Tamil plantation workers returned from Kerala by 18 December.
- Courts: Level held at 136 ft in 2011, raised to 142 ft by the 2014 judgment; review dismissed.
Where it stands in 2025-26
In January 2025 Justice Hrishikesh Roy declined to treat the matter as urgent. He said the dam "has outlasted 2.5 times its life" LiveLaw. In October 2025 a bench of Chief Justice B R Gavai and Justice K Vinod Chandran issued notice on a PIL seeking a new dam. It observed that "some directions may be needed for strengthening the existing dam" Onmanorama.
At the Southern Zonal Council on 20 August 2026, Kerala Chief Minister V D Satheesan offered to pay for a new dam and leave its design, site and construction to Tamil Nadu, with all its water going to Tamil Nadu. Onmanorama reported that Tamil Nadu Chief Minister Joseph Vijay repeated his state's demand to raise the level Onmanorama The News Minute.
From 1 to 3 September 2026 a five-member panel led by former NHPC chief Balraj Joshi inspected the dam. Its review followed a 2022 Supreme Court direction ETV Bharat Onmanorama. Kerala asked it to keep to terms of reference fixed in August 2025, and Joshi said the report would reach the National Dam Safety Authority within 10 to 15 days Deccan Chronicle. No report on its findings was found as of 12 October 2026.
Questions people ask
Why did the Mullaperiyar protests break out in 2011?
Tremors in Idukki in 2011 led Kerala's parties to warn that the old dam could fail. They demanded a lower water level and a new dam, and Tamil Nadu, which relies on the water, opposed both.
What happened at Kumily in December 2011?
Kumily is the Kerala border town nearest the dam. After a Tamil workers' vehicle was attacked there on 5 December, crowds in Tamil Nadu blockaded the highway and marched towards Kumily. Police on the Tamil Nadu side used lathicharges, and on 11 December 50 people were injured.
What did the Supreme Court decide in 2014?
On 7 May 2014 a Constitution Bench struck down Kerala's 2006 law capping the level at 136 ft, allowed Tamil Nadu to raise it to 142 ft, and set up a supervisory committee. It said a new dam needs both states' agreement.
Is the Mullaperiyar dam safe?
The court's Empowered Committee found it safe in 2012, and the court relied on that in 2014. Kerala disputes this, and a fresh comprehensive safety review was under way in September 2026.
Has Kerala's demand for a new dam been accepted?
No. In August 2026 Kerala offered to fund one and give Tamil Nadu all its water, but Tamil Nadu kept to its demand to raise the existing dam's level.
Sources
- Deccan Herald: Kerala MPs to meet PM; Centre says can't impose its decision, 23 Nov 2011
- Khaleej Times: Kerala-TN dam dispute heightens, 29 Nov 2011
- Oneindia: Kerala Congress MPs to fast before Parliament, 28 Nov 2011
- Gulf Times: Tamil Nadu, Kerala MPs meet Singh over dam row, 29 Nov 2011
- Deccan Herald: Kerala for out-of-court settlement of dam row, 29 Nov 2011
- Gulf News: Total shutdown in five districts, 30 Nov 2011
- Tribune: Jayalalithaa letter; Chandy on safety, 1 Dec 2011
- Tribune: Dam row reaches the Capital, 3 Dec 2011
- Tribune/PTI: Centre invites officials; panel team to visit dam, 6 Dec 2011
- Gulf News: Dam protests banned in border town, 7 Dec 2011
- Tribune: Rajya Sabha MPs seek PM's intervention, 8 Dec 2011
- Deccan Herald: Human chain in support of dam, 8 Dec 2011
- IANS via Ummid: 208-km human chain formed in Kerala to demand new dam, 8 Dec 2011
- Tribune: Kerala Assembly passes resolution for new dam, 10 Dec 2011
- Deccan Herald: Special TN session to discuss dam, 11 Dec 2011
- Tribune/PTI: Slippers hurled at TN minister at Kumily, 12 Dec 2011
- Gulf News: Farmers trying to enter border town dispersed, 13 Dec 2011
- Tribune/PTI: TN, Kerala adding fuel to fire, says apex court; protests continue in Theni, 14 Dec 2011
- Tribune: Kerala, TN shoot down each other's proposals in SC, 16 Dec 2011
- The Hindu (via India Environment Portal): Farmers demand protection for Mullaperiyar dam, 18 Dec 2011
- Tribune: Chidambaram links Kerala's fears to bypoll, 18 Dec 2011
- Tribune: Chidambaram withdraws remarks, 19 Dec 2011
- PTI via Governance Now: Over 280 Tamil workers from Kerala return to TN, 19 Dec 2011
- Tribune/PTI: PM promises steps for friendly TN-Kerala ties; hundreds held during protest, 27 Dec 2011
- Frontline (via India Environment Portal): Rising resentment, 29 Dec 2011
- Deccan Herald/PTI: Panel submits report to SC on Mullaperiyar, 25 Apr 2012
- Deccan Herald/PTI: Panel says Mullaperiyar dam safe, 4 May 2012
- The Hindu (via India Environment Portal): SC allows TN to increase Mullaperiyar water level, 7 May 2014
- The Hindu (via India Environment Portal): Supreme Court quashes Kerala dam law, 7 May 2014
- LiveLaw: Issues and findings in the Mullaperiyar judgment, May 2014
- Arab News: Kerala protests, Tamil Nadu elated as court raises Mullaperiyar water level, 7 May 2014
- The News Minute/IANS: Kerala passes fourth resolution for new Mullaperiyar dam, 9 Jun 2014
- Deccan Chronicle: Mullaperiyar water level now 141.5 feet, 23 Nov 2014
- The News Minute/IANS: SC rejects Kerala plea for review of Mullaperiyar verdict, 3 Dec 2014
- LiveLaw: Supreme Court downplays dam break apprehension, 28 Jan 2025
- Onmanorama/PTI: SC issues notice on PIL seeking Mullaperiyar dam replacement, 13 Oct 2025
- Onmanorama: Satheesan offers to fund new Mullaperiyar dam, 20 Aug 2026
- The News Minute: Kerala offers Tamil Nadu all water from new Mullaperiyar dam, 21 Aug 2026
- ETV Bharat: Expert panel begins comprehensive safety audit of Mullaperiyar dam, 2 Sep 2026
- Onmanorama: Mullaperiyar dam safety inspection first phase completed, 2 Sep 2026
- Deccan Chronicle/PTI: Keralam seeks Mullaperiyar safety review as per 2025 terms of reference, 3 Sep 2026